Using getopts to process long and short command line options

Question

I wish to have long and short forms of command line options invoked using my shell script.

I know that getopts can be used, but like in Perl, I have not

Answer 1

The accepted answer does a very nice job of pointing out all the shortcomings of bash built-in getopts. The answer ends with:

So while it is possible to write more code to work around the lack of support for long options, this is a lot more work and partially defeats the purpose of using a getopt parser to simplify your code.

And even though I agree in principle with that statement, I feel that the number of times we all implemented this feature in various scripts justifies putting a bit of effort into creating a "standardised", well tested solution.

As such, I've "upgraded" bash built in getopts by implementing getopts_long in pure bash, with no external dependencies. The usage of the function is 100% compatible with the built-in getopts.

By including getopts_long (which is hosted on GitHub) in a script, the answer to the original question can be implemented as simply as:

source "${PATH_TO}/getopts_long.bash"

while getopts_long ':c: copyfile:' OPTKEY; do
    case ${OPTKEY} in
        'c'|'copyfile')
            echo 'file supplied -- ${OPTARG}'
            ;;
        '?')
            echo "INVALID OPTION -- ${OPTARG}" >&2
            exit 1
            ;;
        ':')
            echo "MISSING ARGUMENT for option -- ${OPTARG}" >&2
            exit 1
            ;;
        *)
            echo "Misconfigured OPTSPEC or uncaught option -- ${OPTKEY}" >&2
            exit 1
            ;;
    esac
done

shift $(( OPTIND - 1 ))
[[ "${1}" == "--" ]] && shift