Idiomatic shell code would be: while getopts "ab:" OPTC; do case "$OPTC" in a) MY_FLAG=0 ;; b) MY_FLAG_ARG="$OPTARG" ;;

Idiomatic shell code would be: while getopts "ab:" OPTC; do case "$OPTC" in a) MY_FLAG=0 ;; b) MY_FLAG_ARG="$OPTARG" ;; *) # shell already printed diagnostic to stderr exit 1 ;; esac done shift $((OPTIND - 1)) Yes, I realize it's more difficult to support long options (though not that difficult), but the best tool for the job will rarely check all the boxes. Anyhow, the arguments for long options are weakest in the case of simple shell scripts. (Above code doesn't handle mixed arguments either but GNU-style permuted arguments are evil. But unlike the Bash example the above code does support bundling, which is something I and many Unix users would expect to always be supported.) Also, I realize there's a ton of Bash code that looks exactly like you wrote. But that's on Google--in promoting Bash to the exclusion of learning good shell programming style they've created an army of Bash zombies who try to write Bash code like they would Python or JavaScript code, with predictable results.