Practical UNIX

Selecting From a Menu of Items

If you want your script to give someone a set menu of options and then want to act on his responses, the case statement is a convenient way to do it. It takes the following form:

case value in
   pattern1 )    command
        ...
        ;;
   pattern2 )     command
        ...
        ;;
        ...
   patternx )     command
        ...
        ;;
esac

Here, value is any text string that will be compared with the patterns pattern₁, pattern₂,and so on to pattern_x. The command list following the first pattern that matches value will be executed. Usually, a catch-all pattern (such as *) will be used as the last pattern to catch anything that you weren’t expecting or that the user mistyped. Note the required double semicolons (;;) after the last command in each pattern section. Don’t forget ...