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PASSWD(1) FreeBSD General Commands Manual PASSWD(1)


[править] NAME

    passwd, yppasswd -- modify a user's password

[править] SYNOPSIS

    passwd [-l] [user]
    yppasswd [-l] [-y] [-d domain] [-h host] [-o]


    The passwd utility changes the user's local, Kerberos, or NIS 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 (which may be
    overridden using the login.conf(5) ``minpasswordlen setting for a
    user's login class) and not purely alphabetic.  Its total length must be
    less than _PASSWORD_LEN (currently 128 characters).
    The new password should contain a mixture of upper and lower case charac-
    ters (which may be overridden using the login.conf(5) ``mixpasswordcase
    setting for a user's login class).  Allowing lower case passwords may be
    useful where the password file will be used in situations where only
    lower case passwords are permissible, such as when using Samba to authen-
    ticate Windows clients.  In all other situations, numbers, upper case
    letters and meta characters are encouraged.
    Once the password has been verified, passwd communicates the new password
    information to the Kerberos authenticating host.
    The following option is available:
    -l      Cause the password to be updated only in the local password file,
            and not with the Kerberos database.  When changing only the local
            password, pwd_mkdb(8) is used to update the password databases.
    When changing local or NIS password, the next password change date is set
    according to ``passwordtime capability in the user's login class.
    To change another user's Kerberos password, one must first run kinit(1)
    followed by passwd.  The super-user is not required to provide a user's
    current password if only the local password is modified.


    The passwd utility has built-in support for NIS.  If a user exists in the
    NIS password database but does not exist locally, passwd automatically
    switches into yppasswd mode.  If the specified user does not exist in
    either the local password database or the NIS password maps, passwd
    returns an error.
    When changing an NIS password, unprivileged users are required to provide
    their old password for authentication (the rpc.yppasswdd(8) daemon
    requires the original password before it will allow any changes to the
    NIS password maps).  This restriction applies even to the super-user,
    with one important exception: the password authentication is bypassed for
    the super-user on the NIS master server.  This means that the super-user
    on the NIS master server can make unrestricted changes to anyone's NIS
    password.  The super-user on NIS client systems and NIS slave servers
    still needs to provide a password before the update will be processed.
    The following additional options are supported for use with NIS:
    -y      Override passwd's checking heuristics and forces it into NIS
    -l      When NIS is enabled, the -l flag can be used to force passwd into
            ``local only mode.  This flag can be used to change the entry
            for a local user when an NIS user exists with the same login
            name.  For example, you will sometimes find entries for system
            ``placeholder users such as bin or daemon in both the NIS pass-
            word maps and the local user database.  By default, passwd will
            try to change the NIS password.  The -l flag can be used to
            change the local password instead.
    -d domain
            Specify what domain to use when changing an NIS password.  By
            default, passwd assumes that the system default domain should be
            used.  This flag is primarily for use by the superuser on the NIS
            master server: a single NIS server can support multiple domains.
            It is also possible that the domainname on the NIS master may not
            be set (it is not necessary for an NIS server to also be a
            client) in which case the passwd command needs to be told what
            domain to operate on.
    -h host
            Specify the name of an NIS server.  This option, in conjunction
            with the -d option, can be used to change an NIS password on a
            non-local NIS server.  When a domain is specified with the -d
            option and passwd is unable to determine the name of the NIS mas-
            ter server (possibly because the local domainname is not set),
            the name of the NIS master is assumed to be ``localhost.  This
            can be overridden with the -h flag.  The specified hostname need
            not be the name of an NIS master: the name of the NIS master for
            a given map can be determined by querying any NIS server (master
            or slave) in a domain, so specifying the name of a slave server
            will work equally well.
    -o      Do not automatically override the password authentication checks
            for the super-user on the NIS master server; assume ``old mode
            instead.  This flag is of limited practical use but is useful for

[править] FILES

    /etc/master.passwd  the user database
    /etc/passwd         a Version 7 format password file
    /etc/passwd.XXXXXX  temporary copy of the password file
    /etc/login.conf     login class capabilities database
    /etc/auth.conf      configure authentication services

[править] SEE ALSO

chpass(1) • kinit(1) • login(1) • login.conf(5) • passwd(5) • kerberos(8) • kpasswdd(8) • pw(8) • pwd_mkdb(8) • vipw(8)

    Robert Morris and Ken Thompson, UNIX password security.

[править] NOTES

    The yppasswd command is really only a link to passwd.

[править] HISTORY

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

FreeBSD 9.0 June 6, 1993 FreeBSD 9.0

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