Description:

"File::Which" was created to be able to get the paths to executable programs
on systems under which the `which' program wasn't implemented in the shell.

"File::Which" searches the directories of the user's "PATH" (as returned by
"File::Spec->path()"), looking for executable files having the name specified
as a parameter to "which()". Under Win32 systems, which do not have a notion of
directly executable files, but uses special extensions such as ".exe" and
".bat" to identify them, "File::Which" takes extra steps to assure that you
will find the correct file (so for example, you might be searching for "perl",
it'll try "perl.exe", "perl.bat", etc.)