Forms of Alias Delivery

Addresses in the righthand side of an alias entry can take four forms:

LHS:  user 
LHS:  /file 
LHS:  |program 
LHS:  :include: file

The user specifies final delivery to a user’s mail spool file (subject to change by the user’s ~/.forward file), or delivery to a new address (e.g., newuser or user@newsite). The /file specifies delivery by appending to a file. The |program specifies delivery by piping the message through a program. The :include: specifies processing of a mailing list. The first three are covered here. The last is covered in the next chapter.

These righthand sides can be combined on a single line, where one is separated from another by a comma. For example:

LHS:  user, /file 

Delivery to Users

Any address in the list of addresses to the right of the colon that does not begin with a /, |, or : character is considered the address of a user. The address can be local or remote.

If that user address to the right of the colon is prefixed with a backslash character (\)[2] and the address is a local one, all further aliasing is suppressed (including reading the user’s ~/.forward file), and the message is delivered with the local delivery agent.

Delivery to Files

When any of the addresses to the right of a colon in the alias list begins with a / character, delivery is made by appending the mail message to a file. This is automatic with all modern configuration files, but there are exceptions.[3] Beginning with V8.7 sendmail, any delivery agent for which the F=/

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