We will
cover the other two forms, :include: (for including separate files from within the
aliases file) and ~/.forward (the user??™s personal :include: file), in the next chapter.
Aliasing can be used to handle several complex delivery problems:
??? Delivering mail to a single user under a variety of usernames
??? Distributing a mail message to many users by specifying only a single recipient
name
??? Appending mail to files for archival and other purposes
??? Filtering mail through programs and shell scripts
All the information that is needed to perform these tasks is contained in the
aliases(5) file (which is often also stored in database format to expedite the lookup
process).
12.1 The aliases(5) File
The aliases(5) file is one of several sources that can supply system mail aliases. We
describe it first because it is the most traditional and because it illustrates the syntax
and limitations common to all techniques.
The aliases(5) file is composed of lines of text. Any line that begins with a # is a comment
and is ignored. Empty lines (those that contain only a newline character) are
also ignored. Any line that begins with a space or a tab is joined (appended) to the
line above it. All other lines of text are viewed as alias lines. The format for an alias
line is:
local: alias
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc.
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