Unable to workaround on getopt options

Question

I am trying to play around with getopt options. I want both short options and long options.

For my following test script, it does not produce my required output.

#!/bin/bash
 
options=$(getopt -o d:f:t: -l domain -l from -l to -- "$@")
[ $? -eq 0 ] || { 
    echo "Incorrect options provided"
    exit 1
}
eval set -- "$options"
while true; do
    case "$1" in
    -d | --domain)
        DOMAIN=$2;
        shift 2
        ;;
    -f | --from)
        FROM=$2;
        shift 2
        ;;
    -t | --to)
        TO=$2;
        shift 2
        ;;
    --)
        shift
        break
        ;;
    esac
    shift
done

echo "Domain is $DOMAIN"
echo "From address is $FROM"
echo "To address is $TO"
exit 0;

When I try to run it, nothing happens, it just hangs:

# bash getopt_check.sh -d hello.com  -f from@test.com -t to@test.com

Expecting output:

Domain is hello.com
From address is from@test.com
To address is to@test.com

Running your script with `bash -x` reveals that `getopt` silently removes the `--` in Bash 5.x. On Bash 3.x, it works exactly as you had hoped. Voting to close as lacking trivial debugging effort. — tripleee, May 04 '21 at 06:10
As an aside, shell scripts should usually not have an extension at all; and if you use `.sh`, it implies that your script targets POSIX `sh`, not Bash. — tripleee, May 04 '21 at 06:11
`it does not produce my required output.` what is the required output? — KamilCuk, May 04 '21 at 06:21

KamilCuk · Accepted Answer · 2021-05-04T06:27:38.817

You are shifting 3 values per option, -d hello.com are 2 positions, not three.

-d | --domain)
    ...
    shift 2
    ...
-f | --from)
    ...
    shift 2
    ...
-t | --to)
    ...
    shift 2
    ...
shift             # shift 2 + shift = shift 3!

change it to:

-d|--domain)
    shift
    ...
-f|--from)
    shift
    ...
-t|--to)
    shift
    ...
shift

Prefer to use lower case variables in your script - use upper case for exported variables. Check your script with http://shellcheck.net . Prefer not to use $?, instead check the command in if like if ! options=$(getopt ...); then echo "Incorrect....

while true; do is unsafe, in case you do not handle some option it will endlessly loop. Do while (($#)); do and handle that *) echo "Internal error - I forgot to add case for my option" >&2; exit 1; ;; in the case statement.

Excellent, Thanks a million, that worked. I realized my mistake now :) — vjwilson, May 04 '21 at 06:27

Unable to workaround on getopt options

1 Answers1