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 The change of the group ownership of files inside of the user's
65 home directory is also not done if the home dir owner uid is
66 different from the current or new user id. This is safety measure
67 for special home directories such as /.
68 -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
70 A list of supplementary groups which the user is also a member of.
71 Each group is separated from the next by a comma, with no
72 intervening whitespace. The groups are subject to the same
73 restrictions as the group given with the -g option.
74 If the user is currently a member of a group which is not listed,
76 the user will be removed from the group. This behaviour can be
77 changed via the -a option, which appends the user to the current
78 supplementary group list.
79 -l, --login NEW_LOGIN
81 The name of the user will be changed from LOGIN to NEW_LOGIN.
82 Nothing else is changed. In particular, the user's home directory
83 or mail spool should probably be renamed manually to reflect the
84 new login name.
85 -L, --lock
87 Lock a user's password. This puts a '!' in front of the encrypted
88 password, effectively disabling the password. You can't use this
89 option with -p or -U.
90 Note: if you wish to lock the account (not only access with a
92 password), you should also set the EXPIRE_DATE to 1.
93 -m, --move-home
95 Move the content of the user's home directory to the new location.
96 If the current home directory does not exist the new home directory
97 will not be created.
98 This option is only valid in combination with the -d (or --home)
100 option.
101 usermod will try to adapt the ownership of the files and to copy
103 the modes, ACL and extended attributes, but manual changes might be
104 needed afterwards.
105 -o, --non-unique
107 When used with the -u option, this option allows to change the user
108 ID to a non-unique value.
109 -p, --password PASSWORD
111 The encrypted password, as returned by crypt(3).
112 Note: This option is not recommended because the password (or
114 encrypted password) will be visible by users listing the processes.
115 You should make sure the password respects the system's password
117 policy.
118 -R, --root CHROOT_DIR
120 Apply changes in the CHROOT_DIR directory and use the configuration
121 files from the CHROOT_DIR directory.
122 -P, --prefix PREFIX_DIR
124 Apply changes in the PREFIX_DIR directory and use the configuration
125 files from the PREFIX_DIR directory. This option does not chroot
126 and is intended for preparing a cross-compilation target. Some
127 limitations: NIS and LDAP users/groups are not verified. PAM
128 authentication is using the host files. No SELINUX support.
129 -s, --shell SHELL
131 The name of the user's new login shell. Setting this field to blank
132 causes the system to select the default login shell.
133 -u, --uid UID
135 The new numerical value of the user's ID.
136 This value must be unique, unless the -o option is used. The value
138 must be non-negative.
139 The user's mailbox, and any files which the user owns and which are
141 located in the user's home directory will have the file user ID
142 changed automatically.
143 The ownership of files outside of the user's home directory must be
145 fixed manually.
146 The change of the user ownership of files inside of the user's home
148 directory is also not done if the home dir owner uid is different
149 from the current or new user id. This is safety measure for special
150 home directories such as /.
151 No checks will be performed with regard to the UID_MIN, UID_MAX,
153 SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.
154 -U, --unlock
156 Unlock a user's password. This removes the '!' in front of the
157 encrypted password. You can't use this option with -p or -L.
158 Note: if you wish to unlock the account (not only access with a
160 password), you should also set the EXPIRE_DATE (for example to
161 99999, or to the EXPIRE value from /etc/default/useradd).
162 -v, --add-subuids FIRST-LAST
164 Add a range of subordinate uids to the user's account.
165 This option may be specified multiple times to add multiple ranges
167 to a users account.
168 No checks will be performed with regard to SUB_UID_MIN,
170 SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
171 -V, --del-subuids FIRST-LAST
173 Remove a range of subordinate uids from the user's account.
174 This option may be specified multiple times to remove multiple
176 ranges to a users account. When both --del-subuids and
177 --add-subuids are specified, the removal of all subordinate uid
178 ranges happens before any subordinate uid range is added.
179 No checks will be performed with regard to SUB_UID_MIN,
181 SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
182 -w, --add-subgids FIRST-LAST
184 Add a range of subordinate gids to the user's account.
185 This option may be specified multiple times to add multiple ranges
187 to a users account.
188 No checks will be performed with regard to SUB_GID_MIN,
190 SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
191 -W, --del-subgids FIRST-LAST
193 Remove a range of subordinate gids from the user's account.
194 This option may be specified multiple times to remove multiple
196 ranges to a users account. When both --del-subgids and
197 --add-subgids are specified, the removal of all subordinate gid
198 ranges happens before any subordinate gid range is added.
199 No checks will be performed with regard to SUB_GID_MIN,
201 SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
202 -Z, --selinux-user SEUSER
204 The new SELinux user for the user's login.
205 A blank SEUSER will remove the SELinux user mapping for user LOGIN
207 (if any).
208
210 You must make certain that the named user is not executing any
211 processes when this command is being executed if the user's numerical
212 user ID, the user's name, or the user's home directory is being
213 changed. usermod checks this on Linux. On other platforms it only uses
214 utmp to check if the user is logged in.
215 You must change the owner of any crontab files or at jobs manually.
217 You must make any changes involving NIS on the NIS server.
219
221 The following configuration variables in /etc/login.defs change the
222 behavior of this tool:
223 MAIL_DIR (string)
225 The mail spool directory. This is needed to manipulate the mailbox
226 when its corresponding user account is modified or deleted. If not
227 specified, a compile-time default is used.
228 MAIL_FILE (string)
230 Defines the location of the users mail spool files relatively to
231 their home directory.
232 The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
234 userdel to create, move, or delete the user's mail spool.
235 If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
237 environment variable.
238 MAX_MEMBERS_PER_GROUP (number)
240 Maximum members per group entry. When the maximum is reached, a new
241 group entry (line) is started in /etc/group (with the same name,
242 same password, and same GID).
243 The default value is 0, meaning that there are no limits in the
245 number of members in a group.
246 This feature (split group) permits to limit the length of lines in
248 the group file. This is useful to make sure that lines for NIS
249 groups are not larger than 1024 characters.
250 If you need to enforce such limit, you can use 25.
252 Note: split groups may not be supported by all tools (even in the
254 Shadow toolsuite). You should not use this variable unless you
255 really need it.
256 SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
258 If /etc/subuid exists, the commands useradd and newusers (unless
259 the user already have subordinate group IDs) allocate SUB_GID_COUNT
260 unused group IDs from the range SUB_GID_MIN to SUB_GID_MAX for each
261 new user.
262 The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are
264 respectively 100000, 600100000 and 65536.
265 SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
267 If /etc/subuid exists, the commands useradd and newusers (unless
268 the user already have subordinate user IDs) allocate SUB_UID_COUNT
269 unused user IDs from the range SUB_UID_MIN to SUB_UID_MAX for each
270 new user.
271 The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are
273 respectively 100000, 600100000 and 65536.
274
276 /etc/group
277 Group account information.
278 /etc/gshadow
280 Secure group account information.
281 /etc/login.defs
283 Shadow password suite configuration.
284 /etc/passwd
286 User account information.
287 /etc/shadow
289 Secure user account information.
290 /etc/subgid
292 Per user subordinate group IDs.
293 /etc/subuid
295 Per user subordinate user IDs.
296
298 chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
299 groupdel(8), groupmod(8), login.defs(5), subgid(5), subuid(5),
300 useradd(8), userdel(8).
301shadow-utils 4.6 09/02/2019 USERMOD(8)