1USERMOD(8) System Management Commands USERMOD(8)
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6 usermod - modify a user account
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9 usermod [options] LOGIN
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12 The usermod command modifies the system account files to reflect the
13 changes that are specified on the command line.
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16 The options which apply to the usermod command are:
17 -a, --append
19 Add the user to the supplementary group(s). Use only with the -G
20 option.
21 -c, --comment COMMENT
23 The new value of the user´s password file comment field. It is
24 normally modified using the chfn(1) utility.
25 -d, --home HOME_DIR
27 The user´s new login directory.
28 If the -m option is given, the contents of the current home
30 directory will be moved to the new home directory, which is created
31 if it does not already exist. If the current home directory does
32 not exist the new home directory will not be created.
33 -e, --expiredate EXPIRE_DATE
35 The date on which the user account will be disabled. The date is
36 specified in the format YYYY-MM-DD.
37 An empty EXPIRE_DATE argument will disable the expiration of the
39 account.
40 This option requires a /etc/shadow file. A /etc/shadow entry will
42 be created if there were none.
43 -f, --inactive INACTIVE
45 The number of days after a password expires until the account is
46 permanently disabled.
47 A value of 0 disables the account as soon as the password has
49 expired, and a value of -1 disables the feature.
50 This option requires a /etc/shadow file. A /etc/shadow entry will
52 be created if there were none.
53 -g, --gid GROUP
55 The group name or number of the user´s new initial login group. The
56 group must exist.
57 Any file from the user´s home directory owned by the previous
59 primary group of the user will be owned by this new group.
60 The group ownership of files outside of the user´s home directory
62 must be fixed manually.
63 -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
65 A list of supplementary groups which the user is also a member of.
66 Each group is separated from the next by a comma, with no
67 intervening whitespace. The groups are subject to the same
68 restrictions as the group given with the -g option.
69 If the user is currently a member of a group which is not listed,
71 the user will be removed from the group. This behaviour can be
72 changed via the -a option, which appends the user to the current
73 supplementary group list.
74 -l, --login NEW_LOGIN
76 The name of the user will be changed from LOGIN to NEW_LOGIN.
77 Nothing else is changed. In particular, the user´s home directory
78 or mail spool should probably be renamed manually to reflect the
79 new login name.
80 -L, --lock
82 Lock a user´s password. This puts a ´!´ in front of the encrypted
83 password, effectively disabling the password. You can´t use this
84 option with -p or -U.
85 Note: if you wish to lock the account (not only access with a
87 password), you should also set the EXPIRE_DATE to 1.
88 -m, --move-home
90 Move the content of the user´s home directory to the new location.
91 If the current home directory does not exist the new home directory
92 will not be created.
93 This option is only valid in combination with the -d (or --home)
95 option.
96 usermod will try to adapt the ownership of the files and to copy
99 the modes, ACL and extended attributes, but manual changes might be
100 needed afterwards.
101 -o, --non-unique
103 When used with the -u option, this option allows to change the user
104 ID to a non-unique value.
105 -p, --password PASSWORD
107 The encrypted password, as returned by crypt(3).
108 Note: This option is not recommended because the password (or
111 encrypted password) will be visible by users listing the processes.
112 You should make sure the password respects the system´s password
114 policy.
115 -R, --root CHROOT_DIR
117 Apply changes in the CHROOT_DIR directory and use the configuration
118 files from the CHROOT_DIR directory.
119 -s, --shell SHELL
121 The name of the user´s new login shell. Setting this field to blank
122 causes the system to select the default login shell.
123 -u, --uid UID
125 The new numerical value of the user´s ID.
126 This value must be unique, unless the -o option is used. The value
128 must be non-negative.
129 The user´s mailbox, and any files which the user owns and which are
131 located in the user´s home directory will have the file user ID
132 changed automatically.
133 The ownership of files outside of the user´s home directory must be
135 fixed manually.
136 No checks will be performed with regard to the UID_MIN, UID_MAX,
138 SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.
139 -U, --unlock
141 Unlock a user´s password. This removes the ´!´ in front of the
142 encrypted password. You can´t use this option with -p or -L.
143 Note: if you wish to unlock the account (not only access with a
145 password), you should also set the EXPIRE_DATE (for example to
146 99999, or to the EXPIRE value from /etc/default/useradd).
147 -Z, --selinux-user SEUSER
149 The new SELinux user for the user´s login.
150 A blank SEUSER will remove the SELinux user mapping for user LOGIN
152 (if any).
153
155 You must make certain that the named user is not executing any
156 processes when this command is being executed if the user´s numerical
157 user ID, the user´s name, or the user´s home directory is being
158 changed. usermod checks this on Linux, but only check if the user is
159 logged in according to utmp on other architectures.
160 You must change the owner of any crontab files or at jobs manually.
162 You must make any changes involving NIS on the NIS server.
164
166 The following configuration variables in /etc/login.defs change the
167 behavior of this tool:
168 MAIL_DIR (string)
170 The mail spool directory. This is needed to manipulate the mailbox
171 when its corresponding user account is modified or deleted. If not
172 specified, a compile-time default is used.
173 MAIL_FILE (string)
175 Defines the location of the users mail spool files relatively to
176 their home directory.
177 The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
179 userdel to create, move, or delete the user´s mail spool.
180 If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
182 environment variable.
183 MAX_MEMBERS_PER_GROUP (number)
185 Maximum members per group entry. When the maximum is reached, a new
186 group entry (line) is started in /etc/group (with the same name,
187 same password, and same GID).
188 The default value is 0, meaning that there are no limits in the
190 number of members in a group.
191 This feature (split group) permits to limit the length of lines in
193 the group file. This is useful to make sure that lines for NIS
194 groups are not larger than 1024 characters.
195 If you need to enforce such limit, you can use 25.
197 Note: split groups may not be supported by all tools (even in the
199 Shadow toolsuite). You should not use this variable unless you
200 really need it.
201
203 /etc/group
204 Group account information.
205 /etc/gshadow
207 Secure group account information.
208 /etc/login.defs
210 Shadow password suite configuration.
211 /etc/passwd
213 User account information.
214 /etc/shadow
216 Secure user account information.
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219 chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
220 groupdel(8), groupmod(8), login.defs(5), useradd(8), userdel(8).
221shadow-utils 4.1.5.1 05/10/2016 USERMOD(8)