Ubuntu Commands

ls -l
  List Storage Long
ls -a
  List Storage All
ls -la
  List Storage Long All
ls -lS
  List Storage Sorted

ls *.html *.css *.*
  Filtered list

ls -d*/
  list only directories

ls -l > file1.txt
  Save output of ls to a file

mkdir 'My Files'
mkdir "My Files"
mkdir My\ Files
  To make a directory with a space in the name

mkdir -p parent/child
  to make a directory within a directory that doesnt exist yet

mkdir -p parent/{child1,child2,child3}
  to make a directory within a directory that doesnt exist and make multiple subdirectories

cat
  Allows writing in terminal

cat file1.txt
  Outputs contents of the file

cat file1.txt file2.txt
  Outputs contents of all files in the argument

cat > file1.txt
  All content written in terminal will be outputted to file

cat >> file1.txt
  All content written in terminal will be appended to file

cat -n file1.txt
  Output file contents with line numbers

cat -b file1.txt
  Output file contents with line numbers and ignores empty lines

cat -s file1.txt
  Output file contents but only allow 1 empty line between non empty lines

cat -sb file1.txt
  Output file contents and number only non empty lines

cat file1.txt >> file2.txt
  Append contents of file 1 to file2