From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 20 Aug 1998 09:00:59 -0400
From: presotto@plan9.bell-labs.com presotto@plan9.bell-labs.com
Subject: [9fans] /mail/lib/rewrite
Topicbox-Message-UUID: 7c8aa10e-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19980820130059.93vNFz8JK9ecNCIGvl41WgaPxTptlpYYSXe37OROqYM@z>

# convert source domain address to a chain a@b@c@d...
@([^@!,]*):([^!@]*)@([^!]*)		alias	\2@\3@\1
@([^@!]*),@([^!@,]*):([^!@]*)@([^!]*)	alias	@\1:\3@\4@\2

# convert a chain a@b@c@d... to ...d!c!b!a
([^@]+)@([^@]+)@(.+)	alias	\2!\1@\3
([^@]+)@([^@]+)		alias	\2!\1

is in our local /mail/lib/rewrite.  I didn't realize the
distribution had something else.  Thanks for pointing it
out.