bash: long options parser

getOptionValue.sh

##
 # long option format: --option=value
 #
 # usage: value="$(getOptionValue option "${@}")"
 #        script.sh --pidfile=/run/pidfile.pid ➙ pidfile="$(getOptionValue pidfile "${@}")"
 ##

getOptionValue() {
    local option

    [[ $# -gt 1 ]] || return

    option="--${1}="
    shift

    while [[ $# -gt 0 ]]; do
        [[ "${1:0:${#option}}" = "${option}" ]] && {
            printf "%s" "${1:${#option}}"
            return
        }

        shift
    done
}