NAME    [Toc]    [Back]

     passwd - modify a user's password

SYNOPSIS    [Toc]    [Back]

     passwd [-l] [-y] [-K] [user]

DESCRIPTION    [Toc]    [Back]

     passwd changes the user's local, Kerberos, or  YP  password.
First, the
     user is prompted for their current password.  If the current
password is
     correctly typed, a new password is requested.  The new password must be
     entered twice to avoid typing errors.

     The  new password should be at least six characters long and
not purely
     alphabetic.  Its total  length  must  be  less  than  _PASSWORD_LEN (currently
     128 characters).  A mixture of both lower and uppercase letters, numbers,
     and meta-characters is encouraged.

     The quality of the password can be enforced by specifying an
external
     checking  program  via the ``passwordcheck'' variable in login.conf(5).

     The options are as follows:

     -l      Causes the password to be updated only in the  local
password
             file.    When  changing  only  the  local  password,
pwd_mkdb(8) is used
             to update the password databases.

     -y      Forces the YP password database entry to be changed,
even if the
             user  has  an  entry  in  the  local  database.  The
rpc.yppasswdd(8)
             daemon should be running on the YP master server.

     -K      Forces the change to affect the Kerberos 5 database,
even if the
             user has a password in the local database.  Once the
password has
             been verified, passwd communicates the new  password
information
             to the Kerberos authenticating host.

     This  is the behavior if no flags are specified: if Kerberos
is active
     then passwd will talk to the Kerberos server  (even  if  the
user has an entry
  in  the local database).  If the password is not in the
local password
     database, then an attempt is made to use the YP database.

     The superuser is not required to provide  a  user's  current
password if only
 the local password is modified.

     Which  type of cipher is used to encrypt the password information depends
     on the configuration in login.conf(5).  It can be  different
for local
     (``localcipher'')  and YP (``ypcipher'') passwords.  If none
is specified,
     then blowfish with 6 rounds is used  for  local  (``localcipher'') and old
     is used for YP (``ypcipher'') by default.

FILES    [Toc]    [Back]

     /etc/login.conf     configuration options
     /etc/master.passwd  user database
     /etc/passwd         a Version 7 format password file
     /etc/passwd.XXXXXX  temporary copy of the password file
     /etc/ptmp           lock file for the passwd database

DIAGNOSTICS    [Toc]    [Back]

     Attempting  lock  password  file, please wait or press ^C to
abort

     The password file is currently locked  by  another  process;
passwd will
     keep  trying  to lock the password file until it succeeds or
you hit the
     interrupt character (control-C by default).   If  passwd  is
interrupted
     while  trying  to gain the lock the password changed will be
lost.

     If the process holding the lock was  prematurely  terminated
the lock file
     may be stale and passwd will wait forever trying to lock the
password
     file.  To determine whether a live process is actually holding the lock,
     the admin may run the following:

           $ fstat /etc/ptmp

     If  no process is listed, it is safe to remove the /etc/ptmp
file to clear
     the error.

SEE ALSO    [Toc]    [Back]

     chpass(1),  kinit(1),  login(1),  login.conf(5),  passwd(5),
pwd_mkdb(8),
     vipw(8)

     Robert Morris and Ken Thompson, UNIX password security.

HISTORY    [Toc]    [Back]

     A passwd command appeared in Version 3 AT&T UNIX.

OpenBSD      3.6                           July      24,     1991