getting procmail to pipe to a gzipped file

[mdevin@ozemail.com.au]

I thought I had this worked out, but it doesn't seem to work quite how
it should.  Bascially I want to have mail with a certain subject piped
into a .gz file in my ~/mail directory.

Here is what I had in .procmailrc:

PATH=/usr/bin:/usr/local/bin
MAILDIR=$HOME/mail   # all mailboxes are in mail/
LOGFILE=/dev/null
SHELL=/bin/sh

# testing of gzip pipe
:0 bw:
* ^Subject:.*gzip
| gzip >>testing.gz

Now if I generate mail with Subject: gzip
it doesn't seem to work.  I can see a testing.gz file that has been
created in ~/mail but it is empty.

Why is it not working?

Mark.