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Showing posts from June 29, 2019
Until loop  The  until  loop is very similar to the  while  loop, except that the loop executes until the  TEST-COMMAND  executes successfully. As long as this command fails, the loop continues. The syntax is the same as for the  while  loop: until TEST-COMMAND; do CONSEQUENT-COMMANDS; done The return status is the exit status of the last command executed in the  CONSEQUENT-COMMANDS  list, or zero if none was executed. TEST-COMMAND  can, again, be any command that can exit with a success or failure status, and  CONSEQUENT-COMMANDS  can be any UNIX command, script or shell construct. Example :--            Write a shell script to display first ten positive numbers using until loop.                                     Program num=1 until [ $num –gt 10 ]; do echo num ...