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32 .\" @(#)passwd.1 8.1 (Berkeley) 6/6/93
40 .Nd modify a user's password
54 utility changes the user's local, Kerberos, or NIS password.
55 If the user is not the super-user,
57 first prompts for the current password and will not continue unless the correct
60 When entering the new password, the characters entered do not echo, in order to
61 avoid the password being seen by a passer-by.
64 utility prompts for the new password twice in order to detect typing errors.
66 The new password should be at least six characters long (which
67 may be overridden using the
70 setting for a user's login class) and not purely alphabetic.
71 Its total length must be less than
73 (currently 128 characters).
75 The new password should contain a mixture of upper and lower case
76 characters (which may be overridden using the
79 setting for a user's login class). Allowing lower case passwords may
80 be useful where the password file will be used in situations where only
81 lower case passwords are permissible, such as when using Samba to
82 authenticate Windows clients. In all other situations, numbers, upper
83 case letters and meta characters are encouraged.
85 Once the password has been verified,
87 communicates the new password information to
88 the Kerberos authenticating host.
90 The following option is available:
91 .Bl -tag -width indent
93 Cause the password to be updated only in the local
94 password file, and not with the Kerberos database.
95 When changing only the local password,
97 is used to update the password databases.
99 When changing local or NIS password, the next password change date
102 capability in the user's login class.
104 To change another user's Kerberos password, one must first
109 The super-user is not required to provide a user's current password
110 if only the local password is modified.
114 utility has built-in support for NIS.
115 If a user exists in the NIS password
116 database but does not exist locally,
118 automatically switches into
122 user does not exist in either the local password database of the
127 When changing an NIS password, unprivileged users are required to provide
128 their old password for authentication (the
130 daemon requires the original password before
131 it will allow any changes to the NIS password maps).
132 This restriction applies even to the
133 super-user, with one important exception: the password authentication is
134 bypassed for the super-user on the NIS master server.
136 the super-user on the NIS master server can make unrestricted changes to
137 anyone's NIS password.
138 The super-user on NIS client systems and NIS slave
139 servers still needs to provide a password before the update will be processed.
141 The following additional options are supported for use with NIS:
142 .Bl -tag -width indent
146 checking heuristics and forces
149 When NIS is enabled, the
151 flag can be used to force
156 This flag can be used to change the entry
157 for a local user when an NIS user exists with the same login name.
158 For example, you will sometimes find entries for system
164 in both the NIS password maps and the local user database.
168 will try to change the NIS password.
171 flag can be used to change the local password instead.
173 Specify what domain to use when changing an NIS password.
176 assumes that the system default domain should be used.
178 primarily for use by the superuser on the NIS master server: a single
179 NIS server can support multiple domains.
180 It is also possible that the
181 domainname on the NIS master may not be set (it is not necessary for
182 an NIS server to also be a client) in which case the
184 command needs to be told what domain to operate on.
186 Specify the name of an NIS server.
187 This option, in conjunction
190 option, can be used to change an NIS password on a non-local NIS
192 When a domain is specified with the
196 is unable to determine the name of the NIS master server (possibly because
197 the local domainname isn't set), the name of the NIS master is assumed to
200 This can be overridden with the
203 The specified hostname need not be the name of an NIS master: the
204 name of the NIS master for a given map can be determined by querying any
205 NIS server (master or slave) in a domain, so specifying the name of a
206 slave server will work equally well.
208 Do not automatically override the password authentication checks for the
209 super-user on the NIS master server; assume 'old' mode instead.
211 flag is of limited practical use but is useful for testing.
214 .Bl -tag -width /etc/master.passwd -compact
215 .It Pa /etc/master.passwd
218 a Version 7 format password file
219 .It Pa /etc/passwd.XXXXXX
220 temporary copy of the password file
221 .It Pa /etc/login.conf
222 login class capabilities database
223 .It Pa /etc/auth.conf
224 configure authentication services
239 .%T "UNIX password security"
244 command is really only a link to