2.11BSD/src/man/man5/passwd.5

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.\"	@(#)passwd.5	6.5 (Berkeley) 5/8/89
.\"
.TH PASSWD 5  "May 8, 1989"
.AT 3
.SH NAME
passwd \- password files
.SH DESCRIPTION
.I Passwd
files are files consisting of newline separated records, one per user,
containing ten colon (``:'') separated fields.  These fields are as
follows:
.PP
.RS
 name		user's login name
 password		user's \fIencrypted\fP password
 uid			user's id
 gid			user's login group id
 class		user's general classification (unused)
 change		password change time
 expire		account expiration time
 gecos		general information about the user
 home_dir		user's home directory
 shell		user's login shell
.RE
.PP
The
.I name
field is the login used to access the computer account, and the
.I uid
field is the number associated with it.  They should both be unique
across the system (and often across a group of systems) since they
control file access.
.PP
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.
.PP
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
in the user database.
.PP
The password field is the
.I encrypted
form of the password.
If the
.I password
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.
.PP
The group field is the group that the user will be placed in upon login.
Since this system supports multiple groups (see
.IR groups (1))
this field currently has little special meaning.
.PP
The
.I class
field is currently unused.  In the near future it will be a key to
a
.IR termcap (5)
style database of user attributes.
.PP
The
.I change
field is the number in seconds, GMT, 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.
.PP
The
.I expire
field is the number in seconds, GMT, from the epoch, until the
account expires.
This field may be left empty to turn off the account aging feature.
.PP
The
.I gecos
field normally contains comma (``,'') separated subfields as follows:
.PP
.RS
 name		user's full name
 office		user's office number
 wphone		user's work phone number
 hphone		user's home phone number
.RE
.PP
This information is used by the
.IR finger (1)
program.
.PP
The user's home directory is the full UNIX path name where the user
will be placed on login.
.PP
The shell field is the command interpreter the user prefers.
If the
.I shell
field is empty, the Bourne shell (\fI/bin/sh\fP) is assumed.
.SH "SEE ALSO"
chpass(1), login(1), passwd(1), getpwent(3), mkpasswd(8), vipw(8) adduser(8)
.SH BUGS
User information should (and eventually will) be stored elsewhere.