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Comment by p4cmanus3r | Hacker News Reader

The authors previous article about "...(not) using #!/usr/bin/env whatever" doesn't sit well with me.

"The only reason to start your script with '#!/usr/bin/env <whatever>' is if you expect your script to run on a system where Bash or whatever else isn't where you expect (or when it has to run on systems that have '<whatever>' in different places, which is probably most common for third party packages)."

His very first point is how you should only use it don't know where to expect bash binary, when I feel like, while it's probably safe in most nix os', assuming it limits future enhancements by requiring that binary be in place. However unlikely it would need to or someone would want to move it.

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I've encountered systems that only have bash in /bin/bash, or in /usr/bin/bash, and it's a hell of a pain to have to fix every script when using different distros (I think it must've been an old Fedora and Ubuntu?).

Nowadays, most distros are moving towards having /bin be a symlink to /usr/bin, so it's mattering less and less, but I see no reason not to just do /usr/bin/env which is supposed to be on the same place on every distro.

I use `#!/usr/bin/env bash` because the /bin/bash on macOS is usually stupidly ancient, and I install a recent version of bash to ~/.local/bin/bash

Is it bad? Well it's less secure. But if you're worried about `/usr/bin/env` calling a malicious program then you need to call out the path for every executable in the script and there's a hell of a lot more other things to worry about too.

It's the same for `#!/usr/bin/env python3` in python scripts. Python3 itself might be ancient at system install, but you might need to be using a venv. So /usr/bin/env python3 works correctly while /usr/bin/python3 works incorrectly.

So is it bad? No.

Never thought of it this way; isn’t it always safe to assume env is in PATH?

Maybe `#! env <shell>` could be considered a DSL for hashbangs. My reasoning is that `/usr/bin/env` is the thing that seems to be hard-coded to a system path, in most cases.

I think POSIX requires env but doesn't mandate a location for it.

Some environments (like containers) have no, or extremely incomplete PATHs.

NixOS only has /usr/bin/env and /bin/sh.

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