This recipe failed to run the pipe even though all
patterns matched (as verified by the verbose output):
:0 hc
* ^TOnetcom
* !^FROM_DAEMON
* !^X-Loop: lee(_at_)piclab(_dot_)com
| ( formail -r -A"Precedence: junk" -A"X-Loop: lee(_at_)piclab(_dot_)com";
touch $HOME/reply.sent; cat $HOME/netcom.msg ) | $SENDMAIL -oi -t
By putting the pipe into a shell script, and invoking the
shell script from .procmailrc (so no "SHELLMETAS" characters
were present), it works great. As written above, it fails
without any notice. I had SHELL set correctly to my Korn
shell, which accepts the -c syntax. Very curious, but since
I found the workaround, I will settle for remaining curious.