portable way of locating an executable (like which)

[Nobody]

On Thu, 20 Sep 2012 23:06:46 +0200, Gelonida N wrote:

> I'd like to implement the equivalent functionality of the unix command
> /usr/bin/which
> 
> The function should work under Linux and under windows.

Note that "which" attempts to emulate the behaviour of execvp() etc. The
exec(3) manpage will explain the precise algorithm used (e.g. they skip
files for which the process lacks execute permission).

Also, note that the shell has built-in commands, functions, and aliases in
addition to programs. The "type" built-in command performs a similar
function to "which" but using the shell's semantics. On some systems,
the default configuration may alias "which" to "type".

On Windows, there's a host of different "execute program" interface, all
with subtly different semantics: which extensions they will run, which
extensions can be omitted, which paths are used (e.g. %PATH%, paths
from the registry, current directory).