PASSWD(1)                 BSD General Commands Manual                PASSWD(1)

NAME
     passwd -- modify a user's password

SYNOPSIS
     passwd [-i infosystem [-l location]] [-u authname] [user]

DESCRIPTION
     The passwd utility changes the user's password.  If the user is not the
     super-user, passwd first prompts for the current password and will not
     continue unless the correct password is entered.

     When entering the new password, the characters entered do not echo, in
     order to avoid the password being seen by a passer-by.  The passwd util-
     ity prompts for the new password twice in order to detect typing errors.

     The new password should be at least six characters long and not purely
     alphabetic.  Its total length should be less than _PASSWORD_LEN (cur-
     rently 128 characters), although some directory systems allow longer
     passwords.  Numbers, upper case letters, and meta characters are encour-
     aged.

     Once the password has been verified, passwd communicates the new password
     to the directory system.

     -i infosystem
           This option specifies where the password update should be applied.
           Under Mac OS X 10.5 and later, supported directory systems are:

           PAM   (default) Pluggable Authentication Modules.

           opendirectory
                 A system conforming to Open Directory APIs and supporting
                 updates (including LDAP, etc).  If no -l option is specified,
                 the search node is used.

           file  The local flat-files (included for legacy configurations).

           nis   A remote NIS server containing the user's password.

     -l location
           This option causes the password to be updated in the given location
           of the chosen directory system.

           for file,
                 location may be a file name (/etc/master.passwd is the
                 default)

           for nis,
                 location may be a NIS domainname

           for opendirectory,
                 location may be a directory node name

           for PAM,
                 location is not used

     -u authname
           This option specifies the user name to use when authenticating to
           the directory node.

     user  This optional argument specifies the user account whose password
           will be changed.  This account's current password may be required,
           even when run as the super-user, depending on the directory system.

FILES
     /etc/master.passwd  The user database
     /etc/passwd         A Version 7 format password file
     /etc/passwd.XXXXXX  Temporary copy of the password file

SEE ALSO
     chpass(1), login(1), dscl(1), passwd(5), pwd_mkdb(8), vipw(8)

     Robert Morris and Ken Thompson, UNIX password security.

HISTORY
     A passwd command appeared in Version 6 AT&T UNIX.

Mac OS X                        August 18, 2008                       Mac OS X