Bash
└─ Positional parameters

To parse positional parameters in Bash, you can use the getopts builtin.

It's syntax is getopts optstring name, where optstring contains the option characters to be recognized. If a character is followed by a colon, the option is expected to have an argument, which should be separated from it by white space. name is the name of the variable to put the current option in. The value of an argument is stored in OPTARG.

See man bash for more information.

To add support for long option names, you can make use of the set builtin to add a single letter option to the positional parameters if a long option is found. Here's an example of that:

function handle_args()
{
    for arg in "$@"; do
        shift
        case "$arg" in
        "--debug") set -- "$@" '-d' ;;
        "--help") set -- "$@" '-h' ;;
        "--ignore") set -- "$@" '-i' ;;
        "--name") set -- "$@" '-n' ;;
        "--publish") set -- "$@" '-p' ;;
        *) set -- "$@" "$arg" ;;
        esac
    done

    while getopts ":dhin:p" opt; do
        case $opt in
        d) option_debug_enabled=true ;;
        h)
            echo "$0 usage:"
            echo "    -d, --debug   Enable debug messages"
            echo "    -h, --help    Show the usage message"
            echo "    -i, --ignore  Ignore existing packages"
            echo "    -n, --name    Build the package with this name"
            echo "    -p, --publish Publish the packages"
            exit 0
            ;;
        i) option_ignore_enabled=true ;;
        n) option_package_name="$OPTARG" ;;
        p) option_publish_enabled=true ;;
        *) warn "unknown option $OPTARG" ;;
        esac
    done
}