help: mention that fd detects executables by file permissions

[matu3ba]

Detecting an executable efficiently is not simple: https://stackoverflow.com/questions/4458120/search-for-executable-files-using-find-command

fd uses the executable bit of the file permissions, which should be mentioned in the help page.

[sharkdp]

I was not aware of this behavior. I think we should probably change the behavior of fd --type executable here to follow what find -executable does. What do others think?

[tavianator]

I'd be in favor of that. We can use the same library we do on Windows since #1061

[Ptipiak]

As the last comment suggest I've made a pull request to use the faccess library,
I haven't find a way to implement the test for this behaviour, I'd like to know if it's relevant to do so ?

[tavianator]

The easiest test is something like touch file && chmod 005 file && fd --type executable file

[sharkdp]

@Ptipiak Writing an integration test for this would be great.

[Ptipiak]

Hi, I though about it right away, although I'm not sure how to create a file with a specific chmod in Rust, I might need to add a package

[tmccombs]

I think nix has chmod function, although you might need to enable an additional feature for it.