Still don't do this. If you use bash specific syntax with this head, that's a bashism and causes issues with people using zsh for example. Or with Debian/*buntu, who use dash as init shell.

Just use #!/bin/bash or #!/usr/bin/env bash if you're funny.

No no no no no, do not believe this you will shoot yourself in the foot.

https://wiki.debian.org/Shell

Beginning with DebianSqueeze, Debian uses Dash as the target of the /bin/sh symlink. Dash lacks many of the features one would expect in an interactive shell, making it faster and more memory efficient than Bash.

From DebianSqueeze to DebianBullseye, it was possible to select bash as the target of the /bin/sh symlink (by running dpkg-reconfigure dash). As of DebianBookworm, this is no longer supported.

It is a symlink, but bash will automatically enable posix compliance mode if you use it. So any bash specific features will bomb out unless you explicitly reset it in the script.

Wut that is not even the case for Ubuntu. You're probably thinking of dash example:

sh -c '[[ true ]] && echo ya' 
# sh: 1: [[: not found

bash -c '[[ true ]] && echo ya' 
# ya

i thought most unix-like systems had it symlinked to a shell like dash. it's what i have on my system (void linux), of course not as an interactive shell lol

i use #!/bin/sh for posix scripts and #!/usr/bin/env bash for bash scripts. #!/bin/sh works for posix scripts since even if it's symlinked to bash, bash still supports posix features.

macOS
Debian
Ubuntu