System Administration Guide, Volume 2

Aliases File

An aliases file contains a list of aliases that share the same user ID.

Each entry is in this form:

uid=alias1=alias2=alias3=...

uid

Shared user ID. 

aliasn

User account sharing the user ID. 

For example, the following entry lists the user ID 0 being shared by sysadm and root:

0=root=sysadm