The Alias file for mail delivery is the file

	/etc/MailAliases

Each line of the alias file has the format:

match : alias

Where:

	alias       :=  simple-list
		    |   "<" alias-file
		    |   "=" UNIX-group
		    |   "*"

	simple-list :=  simple-name
		    |   simple-list, simple-name

Alias-file is a fully qualified UNIX file name.  UNIX-group is a
group name from /etc/group.  A simple-name is a local user login
name, including only alphanumerics, `.' and `-'.  Throughout this
file case is ignored, except for alias-file.

In match, a trailing * on a name will match anything. (See example
below.)

The procedure for mail aliasing is:

1) Build a list of all addresses from the message to be
   delivered, eliminating duplicates.

2) For each line in the alias file, compare "match" against all
   of the existing addresses.  If a match, remove the matched
   name from the address list, and add each new alias name to the
   address list if it is not already on the list.

Since the alias file is read line by line, forward references
work, but backward references are not recognized, thus, there is
no recursion.

E.g.:

Borden: bruce
Bruce: bsb
Wharman: mike
ASRL: bsb, mike, obrien, giarla
UNIX-committee: < /usr/people/unix-committee
System: = sys
Everyone: *
news.*: news
   ...

In the "unix-committee" example, the file "/usr/people/unix-
committee" contains one simple-name, or a list of comma separated
simple-names.  A new-line will be treated as a blank in this
file, s.a.

	foo, fie,
	fum, fiddle

In the "system" case, the names from the group "sys" will be used
as the expanded name list.

In the "news.*" case, all names of the form "news.<anything>" will
be mapped to "news".  This is used for the MH news facility.

Bruce Borden    October 1979