1USERMOD(8) System Management Commands USERMOD(8)
2
6 usermod - modify a user account
7
9 usermod [options] LOGIN
10
12 The usermod command modifies the system account files to reflect the
13 changes that are specified on the command line.
14
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
98 the modes, ACL and extended attributes, but manual changes might be
99 needed afterwards.
100 -o, --non-unique
102 When used with the -u option, this option allows to change the user
103 ID to a non-unique value.
104 -p, --password PASSWORD
106 The encrypted password, as returned by crypt(3).
107 Note: This option is not recommended because the password (or
109 encrypted password) will be visible by users listing the processes.
110 You should make sure the password respects the system's password
112 policy.
113 -R, --root CHROOT_DIR
115 Apply changes in the CHROOT_DIR directory and use the configuration
116 files from the CHROOT_DIR directory.
117 -P, --prefix PREFIX_DIR
119 Apply changes in the PREFIX_DIR directory and use the configuration
120 files from the PREFIX_DIR directory. This option does not chroot
121 and is intended for preparing a cross-compilation target. Some
122 limitations: NIS and LDAP users/groups are not verified. PAM
123 authentication is using the host files. No SELINUX support.
124 -s, --shell SHELL
126 The name of the user's new login shell. Setting this field to blank
127 causes the system to select the default login shell.
128 -u, --uid UID
130 The new numerical value of the user's ID.
131 This value must be unique, unless the -o option is used. The value
133 must be non-negative.
134 The user's mailbox, and any files which the user owns and which are
136 located in the user's home directory will have the file user ID
137 changed automatically.
138 The ownership of files outside of the user's home directory must be
140 fixed manually.
141 No checks will be performed with regard to the UID_MIN, UID_MAX,
143 SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.
144 -U, --unlock
146 Unlock a user's password. This removes the '!' in front of the
147 encrypted password. You can't use this option with -p or -L.
148 Note: if you wish to unlock the account (not only access with a
150 password), you should also set the EXPIRE_DATE (for example to
151 99999, or to the EXPIRE value from /etc/default/useradd).
152 -v, --add-subuids FIRST-LAST
154 Add a range of subordinate uids to the user's account.
155 This option may be specified multiple times to add multiple ranges
157 to a users account.
158 No checks will be performed with regard to SUB_UID_MIN,
160 SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
161 -V, --del-subuids FIRST-LAST
163 Remove a range of subordinate uids from the user's account.
164 This option may be specified multiple times to remove multiple
166 ranges to a users account. When both --del-subuids and
167 --add-subuids are specified, the removal of all subordinate uid
168 ranges happens before any subordinate uid range is added.
169 No checks will be performed with regard to SUB_UID_MIN,
171 SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
172 -w, --add-subgids FIRST-LAST
174 Add a range of subordinate gids to the user's account.
175 This option may be specified multiple times to add multiple ranges
177 to a users account.
178 No checks will be performed with regard to SUB_GID_MIN,
180 SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
181 -W, --del-subgids FIRST-LAST
183 Remove a range of subordinate gids from the user's account.
184 This option may be specified multiple times to remove multiple
186 ranges to a users account. When both --del-subgids and
187 --add-subgids are specified, the removal of all subordinate gid
188 ranges happens before any subordinate gid range is added.
189 No checks will be performed with regard to SUB_GID_MIN,
191 SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
192 -Z, --selinux-user SEUSER
194 The new SELinux user for the user's login.
195 A blank SEUSER will remove the SELinux user mapping for user LOGIN
197 (if any).
198
200 You must make certain that the named user is not executing any
201 processes when this command is being executed if the user's numerical
202 user ID, the user's name, or the user's home directory is being
203 changed. usermod checks this on Linux. On other platforms it only uses
204 utmp to check if the user is logged in.
205 You must change the owner of any crontab files or at jobs manually.
207 You must make any changes involving NIS on the NIS server.
209
211 The following configuration variables in /etc/login.defs change the
212 behavior of this tool:
213 MAIL_DIR (string)
215 The mail spool directory. This is needed to manipulate the mailbox
216 when its corresponding user account is modified or deleted. If not
217 specified, a compile-time default is used.
218 MAIL_FILE (string)
220 Defines the location of the users mail spool files relatively to
221 their home directory.
222 The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
224 userdel to create, move, or delete the user's mail spool.
225 If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
227 environment variable.
228 MAX_MEMBERS_PER_GROUP (number)
230 Maximum members per group entry. When the maximum is reached, a new
231 group entry (line) is started in /etc/group (with the same name,
232 same password, and same GID).
233 The default value is 0, meaning that there are no limits in the
235 number of members in a group.
236 This feature (split group) permits to limit the length of lines in
238 the group file. This is useful to make sure that lines for NIS
239 groups are not larger than 1024 characters.
240 If you need to enforce such limit, you can use 25.
242 Note: split groups may not be supported by all tools (even in the
244 Shadow toolsuite). You should not use this variable unless you
245 really need it.
246 SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
248 If /etc/subuid exists, the commands useradd and newusers (unless
249 the user already have subordinate group IDs) allocate SUB_GID_COUNT
250 unused group IDs from the range SUB_GID_MIN to SUB_GID_MAX for each
251 new user.
252 The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are
254 respectively 100000, 600100000 and 10000.
255 SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
257 If /etc/subuid exists, the commands useradd and newusers (unless
258 the user already have subordinate user IDs) allocate SUB_UID_COUNT
259 unused user IDs from the range SUB_UID_MIN to SUB_UID_MAX for each
260 new user.
261 The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are
263 respectively 100000, 600100000 and 10000.
264
266 /etc/group
267 Group account information.
268 /etc/gshadow
270 Secure group account information.
271 /etc/login.defs
273 Shadow password suite configuration.
274 /etc/passwd
276 User account information.
277 /etc/shadow
279 Secure user account information.
280 /etc/subgid
282 Per user subordinate group IDs.
283 /etc/subuid
285 Per user subordinate user IDs.
286
288 chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
289 groupdel(8), groupmod(8), login.defs(5), subgid(5), subuid(5),
290 useradd(8), userdel(8).
291shadow-utils 4.6 11/08/2018 USERMOD(8)