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Bourne/bash shell scripts: case statement

The case statement is an elegant replacement for if/then/else if/else statements when making numerous comparisons. This recipe describes the case statement syntax for the Bourne shells (sh, ksh, bash, zsh, etc.).

Code:

case "$var" in 
    value1) 
         commands; 
         ;; 
    value2) 
         commands; 
         ;; 
    *) 
         commands; 
         ;; 
esac

The case statement compares the value of the variable ($var in this case) to one or more values (value1, value2, ...). Once a match is found, the associated commands are executed and the case statement is terminated. The optional last comparison *) is a default case and will match anything.

For example, branching on a command line parameter to the script, such as 'start' or 'stop' with a runtime control script. The following example uses the first command line parameter ($1):

Code:

case "$1" in 
     'start') 
         /usr/app/startup-script 
         ;; 
     'stop') 
         /usr/app/shutdown-script 
         ;; 
     'restart') 
         echo "Usage: $0 [start|stop]" 
         ;; 
esac

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THE TECHNO CLUB [ TECHNOWORLDINC.COM ] => Shell Script => Topic started by: Mark David on March 16, 2007, 01:30:01 PM