A frequently asked question is:
which foo tells me something, but it doesn't correspond to what happens when I actually run
foo, what's going on?
Is there one that we can consider to be canonical, so we can close the others as duplicates? Here, canonical means an answer that explains that
which doesn't use the running shell's
PATH and the asker should use
If we don't have one already, let's make one, possibly by editing an existing question.