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   1 The Alias file for mail delivery is the file
   2
   3         /etc/MailAliases
   4
   5 Each line of the alias file has the format:
   6
   7 match : alias
   8
   9 Where:
  10
  11         alias       :=  simple-list
  12                     |   "<" alias-file
  13                     |   "=" UNIX-group
  14                     |   "*"
  15
  16         simple-list :=  simple-name
  17                     |   simple-list, simple-name
  18
  19 Alias-file is a fully qualified UNIX file name.  UNIX-group is a
  20 group name from /etc/group.  A simple-name is a local user login
  21 name, including only alphanumerics, `.' and `-'.  Throughout this
  22 file case is ignored, except for alias-file.
  23
  24 In match, a trailing * on a name will match anything. (See example
  25 below.)
  26
  27 The procedure for mail aliasing is:
  28
  29 1) Build a list of all addresses from the message to be
  30    delivered, eliminating duplicates.
  31
  32 2) For each line in the alias file, compare "match" against all
  33    of the existing addresses.  If a match, remove the matched
  34    name from the address list, and add each new alias name to the
  35    address list if it is not already on the list.
  36
  37 Since the alias file is read line by line, forward references
  38 work, but backward references are not recognized, thus, there is
  39 no recursion.
  40
  41 E.g.:
  42
  43 Borden: bruce
  44 Bruce: bsb
  45 Wharman: mike
  46 ASRL: bsb, mike, obrien, giarla
  47 UNIX-committee: < /usr/people/unix-committee
  48 System: = sys
  49 Everyone: *
  50 news.*: news
  51    ...
  52
  53 In the "unix-committee" example, the file "/usr/people/unix-
  54 committee" contains one simple-name, or a list of comma separated
  55 simple-names.  A new-line will be treated as a blank in this
  56 file, s.a.
  57
  58         foo, fie,
  59         fum, fiddle
  60
  61 In the "system" case, the names from the group "sys" will be used
  62 as the expanded name list.
  63
  64 In the "news.*" case, all names of the form "news.<anything>" will
  65 be mapped to "news".  This is used for the MH news facility.
  66
  67 Bruce Borden    October 1979