which should take an optional parameter...the paths to search

[amoffat]

and Command should be able to take an optional list of paths to manually search for the program, which get passed to which

[mandarvaze]

Should this optional parameter take precedence over default search path ?
e.g. If I have "ls" in "/my/home/dir" - which "ls" should which return ? ("/bin/ls" or "/my/home/dir/ls")

import sh
sh.which("ls", "/my/home/dir")

I think it should return /my/home/dir/ls otherwise user would not have passed additional argument

Also, I assume that optional path would be a list, right ?

[amoffat]

You've got it right @mandarvaze

The idea I was going for was the constructor would take an optional param for paths that defaults to None. If it's None, the paths are constructed to be either an empty list (in the case of "PATH" not in os.environ) or the list of your environment paths: https://github.com/amoffat/sh/blob/master/sh.py#L311-L313, which would then be passed into which (and the existing logic in which refactored out)

It's not super complex but would allow people to override where their programs are searched for without needing to modify their PATH