Compare multiple string in case shell script

Question

I am comparing string in case statement as below : input variable can be D P KL ...

case $input in
      D|P|Q|L1|L2)
         val="Hello";;
      DD|DE|DF|CA)
          val="Hi" ;;
      MM|KL||TK|SZ)
         val="Bye" ;;
         echo $input

input variable not printing anything..

Answer 1

There are two main issues in you script:

1. The case statement is not closed by esac.
2. The third pattern contains || which is a syntax error in most Bourne-like shells (use '' or "" or an expansion that resolves to an empty value to match on the empty string portably)

It's unclear what your script is actually doing, so I'm speculating a bit and wrote this:

#!/bin/sh

input="$1"

case "$input" in
      D|P|Q|L1|L2)
          val='Hello' ;;
      DD|DE|DF|CA)
          val='Hi' ;;
      MM|KL|""|TK|SZ)
          val='Bye' ;;
      *)
          echo 'error' >&2
          exit 1
esac

printf 'input was "%s", val is "%s"\n' "$input" "$val"

Testing it:

$ ./script.sh D
input was "D", val is "Hello"

$ ./script.sh MM
input was "MM", val is "Bye"

$ ./script.sh BOO
error