which and PATH

[Michael ODonnell]

The builtin help provided by bash is pretty good
and it tells you that if you say:

   type -a someFileName

...it'll tell you (in order) about "all of the places
that contain an executable named 'someFileName'.
This includes aliases, builtins, and functions" [etc...]

So, if I say:

   type -a vi

...I see this:

   vi is /etc/alternatives/vi
   vi is /usr/bin/vi
   vi is /usr/bin/X11/vi

More info available from bash thus:

   help type