1MH-ALIAS(5)                   File Formats Manual                  MH-ALIAS(5)
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NAME

6       mh-alias - format of nmh email-address alias files
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DESCRIPTION

9       Each line of an nmh alias file takes one of the following forms:
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11            alias : address-group
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13            alias ; address-group
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15            < alias-file
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17            ; | : | # comment
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19       where:
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21            address-group  := address-list
22                           |  < file
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24            address-list   := address
25                           |  address-list, address
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27       Continuation  lines end with “\” followed by a newline character.  This
28       also applies to comment lines.  Thus, the line following  a  “\”-termi‐
29       nated comment line is a continuation of that comment line.
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31       Alias-file and file are Unix file names.  Alias file contents are case-
32       insensitive, with the exception of filesystem path names.
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34       If the line starts with a “<”, the file named after the “<” is read for
35       more  alias definitions.  The reading is done recursively, so a “<” may
36       occur in the beginning of an alias file with the expected results.
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38       If the address-group starts with a “<”, the file named after the “<” is
39       read and its contents are added to the address-list for the alias.
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41       In  match,  a  trailing  “*” on an alias will match just about anything
42       appropriate.
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44       An approximation of the way aliases are resolved at posting time is:
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46       1)     Build a list of all addresses from the message to be  delivered,
47              eliminating duplicate addresses.
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49       2)     For  those addresses in the message that have no host specified,
50              perform alias resolution.
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52       3)     For each line in the alias file, compare “alias” against all  of
53              the  existing addresses.  If a match, remove the matched “alias”
54              from the address list, and add each new address in the  address-
55              group to the address list if it is not already on the list.  The
56              alias itself is not usually  output,  rather  the  address-group
57              that  the alias maps to is output instead.  If “alias” is termi‐
58              nated with a “;” instead of a “:”, then both the “alias” and the
59              address  are output in the correct format (with the alias quoted
60              if necessary and the address wrapped in <>).
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62       Since the mh-alias file is read line by line, forward references  work,
63       but backward references are not recognized.
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65   Example Alias File
66            </etc/nmh/BBoardAliases
67            sgroup: fred, fear, freida
68            fred: frated@UCI.example
69            b-people: Blind List: bill, betty
70            Unix-committee: <unix.aliases
71            news.*: news
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73       The  first  line says that more aliases should immediately be read from
74       the file /etc/nmh/BBoardAliases.  Next, “sgroup” is defined as an alias
75       for  three  names,  and  one of them, “fred”, is a forward reference to
76       another alias for “frated@UCI.example”.
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78       The alias “b-people” is a  blind  list  which  includes  the  addresses
79       “bill”  and  “betty”; the message will be delivered to those addresses,
80       but the message  header  will  show  only  “Blind  List:  ;”  (not  the
81       addresses).  The alias must not be terminated with, or contain, a semi‐
82       colon.  Note that blind lists are not supported with the  sendmail/pipe
83       mail transport method.
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85       The  definition  of  “Unix-committee”  is  given  by  reading  the file
86       unix.aliases in the user's nmh directory.
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88       Lastly, “news.anything” is aliased to “news”; the  full  stop  is  just
89       another literal character.
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PROFILE COMPONENTS

92       Aliasfile:          Default alias file.
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FILES

95       /etc/nmh/MailAliases
96                           System-wide default alias file.
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SEE ALSO

99       ali(1), send(1), whom(1), getgrent(3), getpwent(3), post(8)
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BUGS

102       Although  the  forward-referencing  semantics of mh-alias files prevent
103       recursion, the alias-file directive may defeat this.  Since the  number
104       of  file  descriptors is finite, such infinite recursion will terminate
105       with a meaningless diagnostic when all the fds are used up.
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107       Earlier versions of this man page showed a semicolon at the end of  the
108       blind  list  example.   That  caused  the  preceding  alias  to  not be
109       expanded.  There must not be a semicolon at the end of, or within,  the
110       address  group  of a blind list.  post will append the semicolon to the
111       blind list name.
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115nmh-1.7.1                         2014-04-18                       MH-ALIAS(5)
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