While Loop Example

• While loop syantax:

      while control-commands; 

do

     other-commands;

  done

Example:

   $ cat while_loop
   #!/bin/bash
   i="0"
   while [ $i -lt 4 ]
   do
   echo "this is whole loop $i"
   i=$i +1
   sleep 10
   done

• The true control statement will execute the script below until CTRL+C is pressed or the script is killed.

  #!/bin/bash
  while true;
  do
  touch PIC-`date +%s`.jpg
  sleep 10
  done

The script in bash -x mode

  ]$ bash -x while_loop
  + true
  ++ date +%s
  + touch PIC-1184928926.jpg
  + sleep 10
  + true
  ++ date +%s
  + touch PIC-1184928936.jpg
  + sleep 10

Reference: http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_09_02.html