procmail..... Try
running the command "which formail".
A warning about a "feature" of 'which': It runs in a subprocess which
clears your environment and re-runs your shell startup file. This means
it MAY give you wrong answers (depending on what you wanted to know). For
example:
Say you
1. have a .profile or .shrc that leaves your path "/usr/bin:$HOME/bin"
2. put formail in ~/my-procmail-stuff
3. put ~/my-procmail-stuff in your .procmailrc and .forward
then 'which formail' will not find it, even though it should still work.
If you think about it, you can create much worse scenarios!!!