# 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
# all mail
plan9\.bell-labs\.com!(.*) | "/mail/lib/qmail '\s' 'net!plan9\.bell-labs\.com'" "'\1'"
.* | "/mail/lib/qmail '\s' 'net!plan9\.bell-labs\.com'" "'&'"
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