Bin bash cleanup

[markus1189]

Motivation for this change

Found #183 and did some cleanup on hard coded /bin/bash paths. The remaining /bin/bash occurrences found via grep '\b/bin/bash/\b' are calls to sed or substitutions.

Some things I like to have reviewed:

1. Would it be even better to use stdenv.shell instead of bash?
2. I assume that the shell scripts from this changeset that use #!/bin/bash are patched automatically somewhere? I still adapted them to use @bash@ to be explicit.
3. Do I have to do some testing for each package changed or does the CI cover this?

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[Mic92]

do you know what shellPath does in this context?

[markus1189]

Oops, this might not make sense for bash itself ;) I only know passthru not exactly what it is used for, though.

[grahamc]

https://github.com/NixOS/nixpkgs/blob/master/doc/stdenv.xml#L255-L280

[markus1189]

Yeah I read the part about passthru but I don't know the relevancy for bash.shellPath ;)

[joachifm]

@markus1189 all packages that can be used as a login shell have to specify a stub shell path, I believe. So this should almost certainly be left alone.

[joachifm]

Suggestion: use stdenv.shell instead of passing in bash everywhere. For files that are to be processed by substituteAll,just use @shell@.

Also consider that stuff that ends up in $out will most likely be subject to shebang patching, though I suppose it doesn't hurt to be explicit.

[markus1189]

I assume @shell@ points to the shell executable like stdenv.shell? Btw how can I find out how that @ interpolation works?

[joachifm]

@shell@ here would be stdenv.shell, yes. There's a builder/bash procedure substituteAll infile outfile that substitutes all @pattern@ with the corresponding shell parameter, so if you have $shell = "${bash}/bin/bash" in the environment when substitution occurs, @shell@ is substituted for that value. From Nix, you'd do something like substituteAll { inherit (stdenv) shell; src = ./foo.sh; }.

[Mic92]

Thanks!