.\" Copyright (c) 1988, 1991 The Regents of the University of California.
.\" %sccs.include.redist.man%
.\" @(#)passwd.5 6.8 (Berkeley) %G%
.Nd format of the password file
files are files consisting of newline separated records, one per user,
containing ten colon (``:'') separated fields. These fields are as
.Bl -tag -width password -offset indent
User's general classification (unused).
General information about the user.
field is the login used to access the computer account, and the
field is the number associated with it. They should both be unique
across the system (and often across a group of systems) since they
While it is possible to have multiple entries with identical login names
and/or identical user id's, it is usually a mistake to do so. Routines
that manipulate these files will often return only one of the multiple
entries, and that one by random selection.
The login name must never begin with a hyphen (``-''); also, it is strongly
suggested that neither upper-case characters or dots (``.'') be part
of the name, as this tends to confuse mailers. No field may contain a
colon (``:'') as this has been used historically to separate the fields
The password field is the
field is empty, no password will be required to gain access to the
machine. This is almost invariably a mistake.
Because these files contain the encrypted user passwords, they should
not be readable by anyone without appropriate privileges.
The group field is the group that the user will be placed in upon login.
Since this system supports multiple groups (see
this field currently has little special meaning.
field is currently unused. In the near future it will be a key to
style database of user attributes.
field is the number in seconds,
from the epoch, until the
password for the account must be changed.
This field may be left empty to turn off the password aging feature.
field is the number in seconds,
from the epoch, until the
This field may be left empty to turn off the account aging feature.
field normally contains comma (``,'') separated subfields as follows:
.Bd -unfilled -offset indent
office user's office number
wphone user's work phone number
hphone user's home phone number
This information is used by the
The user's home directory is the full
The shell field is the command interpreter the user prefers.
If there is nothing in the
User information should (and eventually will) be stored elsewhere.
The password file format has changed since 4.3BSD.
The following awk script can be used to convert your old-style password
file into a new style password file.
are added, but are turned off by default.
Class is currently not implemented, but change and expire are; to set them,
use the current day in seconds from the epoch + whatever number of seconds
.Bd -literal -offset indent
{ print $1 ":" $2 ":" $3 ":" $4 "::0:0:" $5 ":" $6 ":" $7 }