exit(1)                                                             exit(1)

NAME
     exit - terminate a shell script

SYNOPSIS
     exit [exitvalue]

DESCRIPTION
     The shell built-in exit is used to terminate shell scripts. If you
     wish, you can define an exit status for the terminated script by fol-
     lowing exit with a number.

     Without exit, shell scripts terminate:

     -  when the last command has been executed, i.e. when the executing
        shell detects an end-of-file (EOF). The exit status is then the
        status of the last command executed.

     -  when the executing shell cannot find a command or detects a syntax
        error; the exit status is then non-zero.

     If you call exit interactively, the shell in which you are currently
     working terminates.

OPERANDS
     exitvalue
          Any number between 0 and 127. This number defines the exit status
          with which the shell script terminates.

          The exit value can be checked with echo $?.

          exitvalue not specified:

          The exit value of the command executed before the exit call is
          used.

EXAMPLES
     Example 1

     The false command can be implemented by means of the following shell
     script:

     : Shell version of the false command
     : Exit status always 1
     exit 1

     Example 2

     The two shell scripts named end and check will be used to demonstrate
     how the exit status can be evaluated.






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exit(1)                                                             exit(1)

     -  The end script contains the following:

        : Invocation with sh end file
        if [ -f "$1" ]
        then exit 2
        elif [ -d "$1" ]
        then exit 3
        else exit 4
        fi

     -  The check file is scripted as follows:

        : Invocation with sh check file
        sh end "$1"
        case $? in
             2) echo Contents of file $1:; cat $1;;
             3) echo Contents of $1:; ls -l $1|pg;;
             4) echo Entering $1 is meaningless for this script!
        esac

     The shell script check is now initiated:

     $ sh check .profile
     Contents of file .profile:
     HOME=/usr1/rose/src
     export HOME
     .
     .
     .

     The shell script check calls the script named end. This script returns
     an exit status of 2, since .profile is a normal file. The commands
     specified in the case statement under the matching pattern 2 are then
     executed.

     The contents of the above two shell scripts cannot be simply combined
     into a single file, since the exit command terminates the script.

















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exit(1)                                                             exit(1)

     This shell script endaction shows how the exit status can be inter-
     preted within a script:

     : Invocation with sh endaction file
     (if [ -f "$1" ]
        then exit 2
        elif [ -d "$1" ]
        then exit 3
        else exit 4
      fi)
      case $? in
           2) echo Contents of file $1:; cat $1;;
           3) echo Contents of $1:; ls -l $1|pg;;
           4) echo Entering $1 is meaningless for this script!
      esac

     The parentheses around the if statement cause a subshell to be
     invoked. This subshell terminates with the exit status that is speci-
     fied in the relevant exit command. Control is subsequently returned to
     the parent shell, i.e. the shell that processes the endaction script.
     This shell executes the remaining commands.

NOTES
     Some differences in behavior may occur when using exit, depending on
     which shell is being used. The possible differences are not described
     specifically.

SEE ALSO
     false(1), ksh(1), sh(1), exit(2).

























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