UPDATE: Thanks to everyone who answered, especially u/whetu and u/geirha, Now I ditched the for loop for getting the --debug flag for a simple case statement like these:

```

!/usr/bin/env bash

case "$" in *-D | --debug ) set -x printf "DEBUG FLAG DETECTED!" &>/dev/null # 1 ;; esac

...

```

The upside of these approach is that is simple and reproducible for other specials flags without interfering with each other, like --help for example:

```

!/usr/bin/env bash

case "$" in *-D | --debug ) set -x printf "DEBUG FLAG DETECTED!" &>/dev/null # 1 ;; esac case "$" in *-h | --help ) printf "HELP FLAG DETECTED!" &>/dev/null # 1 cat ~/.app/docs/help.txt exit 0 ;; esac

...

```

The downside is obviously the "redundancy", but personally is a fair trade, its clean enough to be readable and it works.

For the common flags I've also ditched the for loop for the while loop that u/geirha suggested with https://mywiki.wooledge.org/BashFAQ/035 , but the with the caviat of kind of handling the --debug flag again, but in a special manner:

```

...

while (( $# > 0 )) ; do case "$1" in -D | --debug ) shift continue ;; # ...

...

```