fix: changed shebang to make scripts more platform independent

[Tygo-van-den-Hurk]

See for example this thread on why its better to use #!/usr/bin/env bash instead of #!/bin/bash. Without this change these scripts will not run on some platforms. This is not a breaking change for the platforms it already currently works on.

PR check-list

• Branch has a clean commit history
• Additional tests are included, if changing behaviors/core code that is testable.
• Proper Copyright + License headers added to applicable files (Generally, we stick to "The ZMK Contributors" for copyrights to help avoid churn when files get edited)
• Pre-commit used to check formatting of files, commit messages, etc.
• Includes any necessary documentation changes.

[caksoylar]

Out of curiosity, under what systems does it not work? I am aware of this practice but I'd like to learn when this becomes an issue in practice for bash.

[Tygo-van-den-Hurk]

Out of curiosity, under what systems does it not work? I am aware of this practice but I'd like to learn when this becomes an issue in practice for bash.

Good question! On NixOS (my system) direct paths are almost always a problem. For example for me, bash located at:

$ which bash
/run/current-system/sw/bin/bash

Which is a symlink to:

/nix/store/f33kh08pa7pmy4kvsmsibda46sh46s66-bash-interactive-5.2p37/bin/bash

But it seems to also be an issue particularly on non-Linux systems. For example, on OpenBSD systems it's usually in /usr/local/bin, cause they install it as an optional package.

[nmunnich]

Should this change also be applied to e.g. app/run-test.sh?

[Tygo-van-den-Hurk]

No but good catch, this is cause that’s using sh instead of bash, and it’s defined in the POSIX standard that sh must be at /bin/sh. So any computer that understands shebangs will also have sh at that location, for any other program other then sh, such as bash this isn’t the case. Though technically #!/usr/bin/env sh would work.

[nmunnich]

I'm now mildly curious about the differences in the script that caused one to end up with sh and the other with bash. The nitpicky part of me wants them all to be consistent. That's not something that should be considered at all for this PR, though.

[Tygo-van-den-Hurk]

Haha no I get it. It feels cleaner if they’re all the same...

As for why, I think that’s cause people just use bash, so they put #!/bin/bash down. I don’t think they use any bash specific features though... so changing it to #!/bin/sh most likely wouldn’t break anything since they follow the same POSIX standard.

[caksoylar]

There are a few bashisms used in the bash scripts, usually you need a bit more diligence when writing POSIX sh. In my experience, it isn't too hard to make them POSIX compatible but replacing some bash features like arrays can be quite annoying.

[petejohanson]

Thanks!