file is used to provide aliases that can be fingered by local
and network users.
This may be useful where a users login name is not the same
as their preferred mail address, or for providing virtual login names
than can be fingered.
Lines beginning with # are comments.
Other lines must consist of an
alias name and a target name separated by a colon.
A target name should be either a user, a forward
reference to another alias or the path of a world readable file.
Where an alias points to a file, the contents of that file will be displayed
when the alias is fingered.