undefined | Better HN

0 pointsjolmg5y ago0 comments

To expand on that pattern:

    while (( $# )); do
      case "$1" in
        -h|--help)
          usage
          exit
          ;;

        -v|--version)
          do_version
          exit
          ;;

        -d|--debug)
          debug=true
          ;;

        -a|--arg)
          arg_value="$2"
          shift
          ;;

        *)
          if [[ ! -v pos1 ]]; then
            pos1="$1"
          elif [[ ! -v pos2 ]]; then
            pos2="$1"
          else
            >&2 printf "%s: unrecognized argument\n" "$1"
            >&2 usage
            exit 1
          fi
      esac

      shift
    done

0 comments

bewuethr5y ago

The one downside of this is that it doesn't handle squeezing flags as in

    foo -da bar

whereas getopts does. On the other hand, with (the Bash built-in) getopts you're limited to single character flags.

Spivak5y ago

You can do that it will just make things a little less pretty.

    while (( $# )); do
        case "$1" in
            -*h*|--help)
                do_help
                exit
                ;;
            -*v*|--version)
                do_version
                exit
                ;;
            -*d*|--debug)
                debug=true
                ;;&
            -*a*|--arg)
                value="$2"
                shift
                ;;&
        esac
        shift
    done

It doesn't support args of the form -avalue but those a pretty uncommon anyway.

jolmgOP5y ago

That wouldn't work in the general case. Those patterns would also match long options. If I add a case pattern `--all)`, and I call the script with `--all`, it's also going to match

  -*a*|--arg)

You could fix that with:

  -a*|-[!-]*a*|--arg)

> It doesn't support args of the form -avalue but those a pretty uncommon anyway.

You could

  -a*|-[!-]*a*|--arg)
    if [[ "$1" != --arg ]]; then
      value="${1#*a}"
    fi
    if [[ ! "$value" ]]; then
      value="$2"
      shift
    fi
  ;;&

Putting the option stuck together to its value has the advantage of working nicely with brace expansion. For example, you can call `strace -p{1111,2222,3333}` to trace those 3 pids and avoid having to type `-p` 3 times.

1 more reply

j / k navigate · click thread line to collapse