scripting - Dynamic case statement in bash

Question

I'm trying to figure out how to create a dynamic case statement in a bash script.

For example, let's say I have the output of an awk statement with the following contents

red
green
blue

In this scenario, the output can change at any time.

I'm trying to then execute different logic if a value is included in this awk output.

So if the data above is in $list, then I'd conceptually like to do something like:

case "${my_var}" in
    $list)
        .....
    something_else)
        .....
esac

I'm trying to use this to build a dynamic custom tab completion function (see http://www.debian-administration.org/article/An_introduction_to_bash_completion_part_2 for some background).

Any ideas?

Thanks.

Answer 1

You can create a dynamic case statement in bash by doing the following:

1) ensure the list is PIPE (|) seperated. IE. red|green|blue

2) wrap your case statement in an eval

For example:

valid="red|green|blue"

eval "case "$choice" in
    $valid)
        echo do something good here
        ;;
    *)
        echo invalid colour
        ;;
esac"

This works for simple variable processing, I can not guarantee this will work in all cases.