usr.sbin/sendmail/cf/m4/postwriterule.m4

divert(10)
#
#  Sendmail
#  Copyright (c) 1983  Eric P. Allman
#  Berkeley, California
#
#  Copyright (c) 1983 Regents of the University of California.
#  All rights reserved.  The Berkeley software License Agreement
#  specifies the terms and conditions for redistribution.
#
#       @(#)postwriterule.m4    1.8 (Berkeley) 1/3/89
#
divert(0)
#################################
#  Final Output Post-rewriting  #
#################################
S4

R@                      $@                              handle <> error addr

# resolve numeric addresses to name if possible
R$*<@[$+]>$*            $:$1<@$[[$2]$]>$3               lookup numeric internet addr

# externalize local domain info
R$*<$+>$*               $1$2$3                          defocus
R@$+:@$+:$+             @$1,@$2:$3                      <route-addr> canonical

# UUCP must always be presented in old form
R$+@$-.UUCP             $2!$1                           u@h.UUCP => h!u

# delete duplicate local names
R$+%$=w@$=w             $1@$w                           u%host@host => u@host
R$+%$=w@$=w.$D          $1@$w                           u%host@host => u@host