Use more convenient and UNIX-agnostic shebang

[dereckson]

When using bash-specific features, scripts using env to call bash
are more convenient, as bash be installed in different places
according the OS.

[shepmaster]

I'd be against doing this in such a limited fashion, considering that we use /bin/bash in so many other contexts:

$ git grep -h '/bin/bash' | sort | uniq -c
   1     useradd --shell /bin/bash -u $LOCAL_USER_ID -o -c "" -m user
  42 #!/bin/bash
   1 export SHELL=/bin/bash

We do have some precedent for using env though:

$ git grep -h '/usr/bin/env' | sort | uniq -c
  10 #!/usr/bin/env python
   1 #!/usr/bin/env python2.7
   1 #!/usr/bin/env rustx

I can't really speak to how dangerous changing all of the shebangs would be though.

[shepmaster]

Can you explain a bit more about why you want to make this change?

[dereckson]

The goal is to ease the testing suite on OpenBSD and other OS where bash isn't shipped by default.

If we switch progressively everything to pure POSIX, we can use the scripts everywhere on the out-of-the-box OS, without having to install bash.

[shepmaster]

If we switch progressively everything to pure POSIX

I wondered if that was the underlying goal. Let's wait for a decision on #45958 then.

[shepmaster]

Based on alexcrichton's comment:

Yes updating the shebang is fine, [...]

I think it makes sense to update these, but I'd prefer that you'd update all the instances of /bin/bash.

[shepmaster]

Ping from triage @dereckson — will you have an opportunity to update the other references soon?

[dereckson]

Okay, so now this commit updates all the relevant shebang, ie the different bash and one python2.7 left.

The only not-env shebang scripts are now:

• #!/bin/false, documented as invalid in header
• #!/bin/sh, apparently universally installed at this path

[shepmaster]

LGTM!

@bors r+ rollup

[bors]

📌 Commit a4b4a73 has been approved by shepmaster

[bors]

⌛ Testing commit a4b4a73 with merge fdfbcf8...