bash4H feb21

######## SUBSHELLS
student@student-virtual-machine:~/bash-scripting$ cat colors
COLOR=red
student@student-virtual-machine:~/bash-scripting$ cat use-colors.sh
#!/bin/bash

echo the color is $COLOR
student@student-virtual-machine:~/bash-scripting$ chmod +x use-colors.sh
student@student-virtual-machine:~/bash-scripting$ ./use-colors.sh
the color is
student@student-virtual-machine:~/bash-scripting$ COLOR=yellow
student@student-virtual-machine:~/bash-scripting$ ./use-colors.sh
the color is
student@student-virtual-machine:~/bash-scripting$ export COLOR=yellow
student@student-virtual-machine:~/bash-scripting$ ./use-colors.sh
the color is yellow
student@student-virtual-machine:~/bash-scripting$ vim use-colors.sh
student@student-virtual-machine:~/bash-scripting$ vim use-colors.sh
student@student-virtual-machine:~/bash-scripting$ cat use-colors.sh
#!/bin/bash

. colors

echo the color is $COLOR
student@student-virtual-machine:~/bash-scripting$ ./use-colors.sh
the color is red

##########
student@student-virtual-machine:~/bash-scripting$ cat je.sh
#!/bin/bash

[ ! -d ~/sysconfig ] && mkdir ~/sysconfig

echo PLANET=moon > ~/sysconfig/planets

. ~/sysconfig/planets

echo Your current planet is $PLANET

##########student@student-virtual-machine:~/bash-scripting$ echo $?
6
student@student-virtual-machine:~/bash-scripting$ cat script8c
#!/bin/bash

if [ ! -f /etc/hostss ]
then
	echo criticial error
	exit 6
fi

echo file does exist


########
#!/bin/bash

sudo useradd $1
#echo useradd $1

if [ $? -eq 0 ]
then
	echo user created successfully
else
	echo user not created successfully
fi

exit 0

#########
student@student-virtual-machine:~/bash-scripting$ cat mz.sh
#!/bin/bash

sudo useradd $1
#echo useradd $1

if [ $? -eq 0 ]
then
	echo user created successfully
else
	echo user not created successfully
fi

exit 0
student@student-virtual-machine:~/bash-scripting$ cat ts.sh
#!/bin/bash

# This is the comment

if sudo useradd $1
then
        echo "User created successfully"
else
        echo "User not created successfully"
fi

exit 0

###########
student@student-virtual-machine:~/bash-scripting$ history
    1  ls
    2  echo $BASH
    3  sudo apt install vim git bash-completion
    4  git clone https://github.com/sandervanvugt/bash-script
    5  git clone https://github.com/sandervanvugt/bash-scripting
    6  cd bash-scripting/
    7  ls
    8  chsh --help
    9  history
   10  ls
   11  vim script1
   12  ls /etc/hosts
   13  echo $?
   14  ls hweriughiuh
   15  echo $?
   16  vim script1
   17  script1
   18  echo $PATH
   19  pwd
   20  ls
   21  ./script1
   22  ls -l
   23  chmod +x script1
   24  ./script1
   25  history
   26  ./countdown 3
   27  vim script2
   28  cat script2
   29  ./script2
   30  ls -l
   31  chmod +x scr*
   32  ls -l
   33  cat script2
   34  ./script2
   35  vim subshell.txt
   36  vim colors
   37  vim use-colors.sh
   38  cat colors
   39  cat use-colors.sh
   40  chmod +x use-colors.sh
   41  ./use-colors.sh
   42  COLOR=yellow
   43  ./use-colors.sh
   44  export COLOR=yellow
   45  ./use-colors.sh
   46  vim use-colors.sh
   47  cat use-colors.sh
   48  ./use-colors.sh
   49  vim use-colors.sh
   50  ./countdown 13
   51  vim je.sh
   52  chmod +x je.sh
   53  ./je.sh
   54  chmod +x je.sh
   55  vim je.sh
   56  ./je.sh
   57  vim je.sh
   58  ./je.sh
   59  vim je.sh
   60  man test
   61  vim je.sh
   62  ./je.sh
   63  vim je.sh
   64  ./je.sh
   65  cat je.sh
   66  history
   67  vim countdown
   68  vim script3
   69  echo $(( 2 * 30 ))
   70  echo $( 2 * 30 )
   71  vim script3
   72  ./script3 a b c d e f g h i jk l m n o p
   73  cat script3
   74  echo $$$$$
   75  echo \$$$$$
   76  echo '$$$$$'
   77  blah lisa
   78  ./countdown 3
   79  vim je.sh
   80  vim je2.sh
   81  chmod +x je2.sh
   82  ./je2.sh
   83  ./je2.sh linda lucy lori
   84  vim je2.sh
   85  vim script4
   86  ./script4 a b c d e
   87  cat script4
   88  vim script4
   89  ./script4 a b c d e
   90  touch iwrhgi
   91  ./countdown 3
   92  vim kc.sh
   93  ip a
   94  chmod +x kc.sh
   95  ./kc.sh 8 1 7 6 5
   96  vim kc.sh
   97  cd /lib
   98  ls
   99  cd kernel/
  100  ls
  101  cd ..
  102  cd
  103  uname -r
  104  find / -name $(uname -r)
  105  sudo find / -name $(uname -r) 2>/dev/null
  106  cd /usr/lib/modules
  107  ls
  108  cd $(uname -r)
  109  cd ..
  110  cd `uname -r`
  111  cd
  112  cd bash-scripting/
  113  ./countdown 3
  114  vim dv.sh
  115  bash dv.sh
  116  ls
  117  vim script6
  118  ./script6 /usr/bin/blah
  119  vim script6
  120  ./script6 /usr/bin/blah
  121  vim script6
  122  ./script6 /usr/bin/blah
  123  vim script6
  124  vim script7
  125  ./countdown 4
  126  ls
  127  vim je2.sh
  128  vim je3.sh
  129  chmod +x je3.sh
  130  ./je3.sh
  131  vim je3.sh
  132  vim script8
  133  cat /etc/passwd
  134  cut -d : -f 1 /etc/passwd
  135  vim script8
  136  sudo useradd alex
  137  sudo useradd alexander
  138  ./script8 alex
  139  ./script8 khkuhi
  140  vim script8
  141  cp script8 script8b
  142  vim script8b
  143  chmod +x script8b
  144  ./script8b alex
  145  ./script8b erblhjki
  146  vim script8b
  147  vim script8c
  148  chmod +x script8c
  149  ./script8c
  150  vim script8c
  151  ./script8c
  152  echo $?
  153  cat script8c
  154  vim users
  155  grep alex users
  156  grep ^alex users
  157  grep alex$ users
  158  grep ^alex$ users
  159  vim script8
  160  vim script8c
  161  man test
  162  test -f /etc/hosts
  163  echo $0
  164  test -f /etc/hosts
  165  echo $?
  166  test ! -f /etc/hosts
  167  echo $?
  168  [ ! -f /etc/hosts ]
  169  echo $?
  170  less /etc/network/if-post-down.d/wireless-tools
  171  vim script8
  172  ./script8 alex
  173  vim script8
  174  ./countdown 12
  175  vim mz.sh
  176  chmod +x mz.sh
  177  ./mz.sh
  178  ./mz.sh bob
  179  vim mz.sh
  180  ./mz.sh
  181  bash -x mz.sh
  182  vim mz.sh
  183  man test
  184  vim mz.sh
  185  ./mz.sh
  186  vim mz.sh
  187  ./mz.sh
  188  vim mz.sh
  189  ./mz.sh bill
  190  cat mz.sh
  191  vim script9
  192  cp script9 script9b
  193  vim script9b
  194  chmod +x script9b
  195  ./script9b
  196  echo $?
  197  ./script9b jhyki
  198  vim script9b
  199  [ -f /etc/khkiu ] || echo failing
  200  [ -f /etc/hosts ] || echo failing
  201  [ -f /etc/hosts ] && echo successfull
  202  [ -f /etc/hosthjgjgys ] && echo successfull
  203  ./countdown 3
  204  vim ts.sh
  205  chmod +x ts.sh
  206  ./ts.sh
  207  ./ts.sh bob
  208  ./ts.sh ben
  209  history
  210  cat mz.sh
  211  cat ts.sh
  212  vim sb.sh
  213  man test
  214  vim sb.sh
  215  chmod +x sb.sh
  216  ./sb.sh
  217  vim sb.sh
  218  ./sb.sh
  219  vim sb.sh
  220  ./sb.sh
  221  ls -l /etc/shadow
  222  ls
  223  vim script10
  224  ./script10 5
  225  vim script11
  226  ./script11 1
  227  vim script11
  228  ./script11 1
  229  vim script11
  230  ./script11 1
  231  bash -x script11 1
  232  vim script11
  233  ./script11 1
  234  bash -x ./script11 1
  235  ls
  236  vim script11
  237  ./script11 1
  238  vim script11
  239  ./script11 1
  240  vim script11
  241  ./script11 1
  242  history