[kibwen]

> then you have to add a shebang line directly to the script itself, which I always feel uncomfortable since it's hard-coded (what if in future I don't want to execute my .py script with `/usr/bin/python` but `/usr/bin/nohtyp`?)

> But I really, really just want to run `hello` to call a `hello.py` script that is in my $PATH.

On Linux I'd say the shebang is still the right tool for this. If you want a lightweight approach, just have a `my_python` symlink in your path, then your shebang can be `/usr/bin/env my_python` (or heck just `/foo/bar/baz/my_python`, /usr/bin/env is already an abstraction).

If you want a more principled approach, look at the `update-alternatives` tool, which provides this sort of abstraction in a more general way: https://linuxconfig.org/how-to-set-default-programs-using-up...

[ffsm8]

> /usr/bin/env is already an abstraction).

Isn't that path and the behavior of the binary defined by POSIX though? I thought it's as stable as you can get.

That's why it's usually recommended that you use /use/bin/env bash vs /bin/bash in the shebang, as the latter isn't defined by POSIX

[rascul]

> Isn't that path and the behavior of the binary defined by POSIX though? I thought it's as stable as you can get.

I don't see anything about the path being defined. Certainly possible I missed it, though.

I'm not able to check right now but I vaguely recall that I've used a system in the past with env in a location other than /usr/bin.

[kibwen]

Yes, env is an abstraction for the sake of portability, but if you're setting up custom indirections then portability probably isn't much of a concern.