Don't do this: you have a bug when "$1" is ''. arg= while [[ "$#" -gt 0 ]]; do case "$1" in --arg) shift; arg="$1" ;; *) help

Don't do this: you have a bug when "$1" is ''. arg= while [[ "$#" -gt 0 ]]; do case "$1" in --arg) shift; arg="$1" ;; *) help; exit 1 ;; esac shift done