passwd(4) passwd(4)
NAME
passwd - password file
SYNOPSIS
/etc/passwd
DESCRIPTION
/etc/passwd is an ASCII file that contains basic information
about each user's account.
Files
/etc/passwd
/etc/shadow
/usr/lib/locale/locale/LC_MESSAGES/uxcore.abi
language-specific
message file [See LANG
on environ(5).]
/var/yp/domainname/passwd.byname Corresponding NIS map
containing password
information. The user
name is the key in the
map.
/var/yp/domainname/passwd.byuid Same as passwd.byname,
except key is user ID
instead of user name.
USAGE
For each authorized user, the passwd file contains a one-line
entry, of the form:
login_name : password : uid : gid : comment : home_dir : login_shell
where:
login_name is the name specified by the user when logging
in. This field contains no uppercase
characters, should not be more than eight
characters long, and should begin with a non-
numeric character (that is, any alphabetic or
special character except colon).
password contains the character x. This field remains
only for compatibility reasons. Password
information is contained in the file
/etc/shadow [see shadow(4)].
Copyright 1994 Novell, Inc. Page 1
passwd(4) passwd(4)
uid is the user's numerical ID for the system,
which should be unique.
gid is the numerical ID of the group to which the
user belongs.
comment is any information you think might be useful to
a user of this file which is not included
elsewhere in the file.
home_dir is the pathname of the directory in which the
user is initially positioned upon logging in.
login_shell is the user's initial shell program. If this
field is empty, the default shell is
/usr/bin/sh.
Fields are separated by a colon; entries, by a new-line.
Comment lines (lines preceded by the # (hash) character) are
not allowed in the /etc/passwd file.
/etc/passwd has general read permission on all systems, and
can be used by routines that map numerical user IDs to names.
The passwd file can also have lines beginning with a + (plus
sign) which means to incorporate entries from the Network
Information Service (NIS). There are three styles of +
entries in the passwd file: by itself, + means to insert the
entire contents of the NIS password file at that point; +name
means to insert the entry (if any) for name from the NIS
service at that point; +@ netgroup means to insert the entries
for all members of the network group netgroup at that point.
If a + name entry has a non-null password, comment, home-dir,
or login-shell field, the value of that field overrides what
is contained in the NIS service. The uid and gid fields
cannot be overridden.
The passwd file can also have lines beginning with a - (minus
sign) which means to disallow entries from the NIS service.
There are two styles of - entries in the passwd file: - name
means to disallow any subsequent entries (if any) for name (in
this file or in the NIS service); -@ netgroup means to
disallow any subsequent entries for all members of the network
group netgroup.
Copyright 1994 Novell, Inc. Page 2
passwd(4) passwd(4)
When the Network Information Service (NIS) is in use, the
local /etc/passwd file is consulted first, then the NIS maps
passwd.byname or passwd.byuid on the NIS server.
Examples
Here is a sample passwd file:
root:x:0:10:God:/:/bin/csh
fred:x:508:10:& Fredericks:/usr2/fred:/bin/csh
+john:
+@documentation:no-login:
+::::Guest
In this example, there are specific entries for users root and
fred, to ensure that they can log in even when the system is
running standalone. The user john will have his password
entry in the NIS service incorporated without change; anyone
in the netgroup documentation will have their password field
disabled, and anyone else will be able to log in with their
usual password, shell, and home directory, but with a comment
field of Guest.
Warnings
To avoid inconsistencies with the I&A security database, NIS
entries should always come at the end of the passwd file.
REFERENCES
getpwent(3C), group(4), login(1), passwd(1), putpwent(3C),
pwconv(1M), shadow(4), unistd(4), useradd(1M), userdel(1M),
usermod(1M)
Copyright 1994 Novell, Inc. Page 3