Using variable as case pattern in Bash

Question

I\'m trying to write a Bash script that uses a variable as a pattern in a case statement. However I just cannot get it to work.

Case statement:

case          


        

Answer 1

(Updated): here's something a bit different, but I hope it works for what you need it for:

#!/bin/bash

pattern1="aaa bbb ccc"
pattern2="hello world"
test=$(echo -e "$pattern1\n$pattern2" | grep -e $1)

case "$test" in
    "$pattern1")
        echo "matched - pattern1"
        ;;
    "$pattern2")
        echo "matched - pattern2"
        ;;
    *)
        echo "didn't match"
        ;;
esac

This makes use of grep to do the pattern matching for you, but still allows you to specify multiple pattern sets to be used in a case-statement structure.

For instance:

• If either aaa, bbb, or ccc is the first argument to the script, this will output matched - pattern1.
• If either hello or world is the first argument, this will output matched - pattern2.
• Otherwise it will output didn't match.

Answer 2

You can use the extglob option:

#! /bin/bash

shopt -s extglob         # enables pattern lists like +(...|...)
test='+(aaa|bbb|ccc)'

for x in aaa bbb ccc ffffd ; do
    echo -n "$x "
    case "$x" in
        $test) echo Matches.
        ;;
        *) echo Does not match.
    esac
done

Answer 3

using eval also works:

eval 'case "$1" in

    '$test')
        echo "matched"
        ;;
    *)
        echo "did not match"
        ;;
esac'