Can a shell script flag have optional arguments if parsing with getopts?

Question

I have a script that I want to run in three ways:

Without a flag -- ./script.sh
With a flag but no parameter -- ./script.sh -u
With a flag that takes a parameter -- ./script.sh -u username

Is there a way to do this?

After reading some guides (examples here and here) it doesn't seem like this is a possibility, especially if I want to use getopts.

Can I do this with getopts or will I need to parse my options another way? My goal is to continue using getopts if I can.

@CharlesDuffy I believe OP is talking about optional **arguments**, not flags. Which I don't think is possible with `getopts`. — PesaThe, Aug 29 '18 at 16:35
Option arguments, not positional arguments, then? *That* makes much more sense. That said, BashFAQ #35 (linked in the question!) *does* show a (non-`getopts`-based) approach that supports their use just fine. — Charles Duffy, Aug 29 '18 at 16:36
If my questions isn't immediately obvious, should I reword it? — Wimateeka, Aug 29 '18 at 16:39
Sure. Actually, I had the misunderstanding, so if you don't mind, I might try to reword a bit myself... — Charles Duffy, Aug 29 '18 at 16:41

Charles Duffy · Answer 1 · 2018-08-29T19:05:39.453

0

The non-getopts example in BashFAQ #35 can cover the use case:

user_set=0  # 1 if any -u is given
user=       # set to specific string for -u, if provided
while :; do
  case $1 in
    -u=*) user_set=1; user=${1#*=} ;;
    -u)   user_set=1
          if [ -n "$2" ]; then
            user=$2
            shift
          fi ;;
    --)   shift; break ;;
    *)    break ;;
  esac
  shift
done

edited Aug 29 '18 at 19:05

answered Aug 29 '18 at 16:51

Charles Duffy

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Forgot a ";;" after the "fi" ... I think. – Andre Gelinas Aug 29 '18 at 18:39

Can a shell script flag have optional arguments if parsing with getopts?

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