1USERADD(8) System Management Commands USERADD(8)
2
6 useradd - create a new user or update default new user information
7
9 useradd [options] LOGIN
10 useradd -D
12 useradd -D [options]
14
16 When invoked without the -D option, the useradd command creates a new
17 user account using the values specified on the command line plus the
18 default values from the system. Depending on command line options, the
19 useradd command will update system files and may also create the new
20 user's home directory and copy initial files.
21 By default, a group will also be created for the new user (see -g, -N,
23 -U, and USERGROUPS_ENAB).
24
26 The options which apply to the useradd command are:
27 --badname
29 Allow names that do not conform to standards.
30 -b, --base-dir BASE_DIR
32 The default base directory for the system if -d HOME_DIR is not
33 specified. BASE_DIR is concatenated with the account name to
34 define the home directory.
35 If this option is not specified, useradd will use the base
37 directory specified by the HOME variable in /etc/default/useradd,
38 or /home by default.
39 -c, --comment COMMENT
41 Any text string. It is generally a short description of the
42 account, and is currently used as the field for the user's full
43 name.
44 -d, --home-dir HOME_DIR
46 The new user will be created using HOME_DIR as the value for the
47 user's login directory. The default is to append the LOGIN name to
48 BASE_DIR and use that as the login directory name. If the directory
49 HOME_DIR does not exist, then it will be created unless the -M
50 option is specified.
51 -D, --defaults
53 See below, the subsection "Changing the default values".
54 -e, --expiredate EXPIRE_DATE
56 The date on which the user account will be disabled. The date is
57 specified in the format YYYY-MM-DD.
58 If not specified, useradd will use the default expiry date
60 specified by the EXPIRE variable in /etc/default/useradd, or an
61 empty string (no expiry) by default.
62 -f, --inactive INACTIVE
64 defines the number of days after the password exceeded its maximum
65 age where the user is expected to replace this password. The value
66 is stored in the shadow password file. An input of 0 will disable
67 an expired password with no delay. An input of -1 will blank the
68 respective field in the shadow password file. See shadow(5)for more
69 information.
70 If not specified, useradd will use the default inactivity period
72 specified by the INACTIVE variable in /etc/default/useradd, or -1
73 by default.
74 -F, --add-subids-for-system
76 Update /etc/subuid and /etc/subgid even when creating a system
77 account with -r option.
78 -g, --gid GROUP
80 The name or the number of the user's primary group. The group name
81 must exist. A group number must refer to an already existing group.
82 If not specified, the behavior of useradd will depend on the
84 USERGROUPS_ENAB variable in /etc/login.defs. If this variable is
85 set to yes (or -U/--user-group is specified on the command line), a
86 group will be created for the user, with the same name as her
87 loginname. If the variable is set to no (or -N/--no-user-group is
88 specified on the command line), useradd will set the primary group
89 of the new user to the value specified by the GROUP variable in
90 /etc/default/useradd, or 1000 by default.
91 -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
93 A list of supplementary groups which the user is also a member of.
94 Each group is separated from the next by a comma, with no
95 intervening whitespace. The groups are subject to the same
96 restrictions as the group given with the -g option. The default is
97 for the user to belong only to the initial group.
98 -h, --help
100 Display help message and exit.
101 -k, --skel SKEL_DIR
103 The skeleton directory, which contains files and directories to be
104 copied in the user's home directory, when the home directory is
105 created by useradd.
106 This option is only valid if the -m (or --create-home) option is
108 specified.
109 If this option is not set, the skeleton directory is defined by the
111 SKEL variable in /etc/default/useradd or, by default, /etc/skel.
112 If possible, the ACLs and extended attributes are copied.
114 -K, --key KEY=VALUE
116 Overrides /etc/login.defs defaults (UID_MIN, UID_MAX, UMASK,
117 PASS_MAX_DAYS and others).
118 Example: -K PASS_MAX_DAYS =-1 can be used when creating an account
120 to turn off password aging. Multiple -K options can be specified,
121 e.g.: -K UID_MIN =100 -K UID_MAX=499
122 -l, --no-log-init
124 Do not add the user to the lastlog and faillog databases.
125 By default, the user's entries in the lastlog and faillog databases
127 are reset to avoid reusing the entry from a previously deleted
128 user.
129 If this option is not specified, useradd will also consult the
131 variable LOG_INIT in the /etc/default/useradd if set to no the user
132 will not be added to the lastlog and faillog databases.
133 -m, --create-home
135 Create the user's home directory if it does not exist. The files
136 and directories contained in the skeleton directory (which can be
137 defined with the -k option) will be copied to the home directory.
138 By default, if this option is not specified and CREATE_HOME is not
140 enabled, no home directories are created.
141 The directory where the user's home directory is created must exist
143 and have proper SELinux context and permissions. Otherwise the
144 user's home directory cannot be created or accessed.
145 -M, --no-create-home
147 Do not create the user's home directory, even if the system wide
148 setting from /etc/login.defs (CREATE_HOME) is set to yes.
149 -N, --no-user-group
151 Do not create a group with the same name as the user, but add the
152 user to the group specified by the -g option or by the GROUP
153 variable in /etc/default/useradd.
154 The default behavior (if the -g, -N, and -U options are not
156 specified) is defined by the USERGROUPS_ENAB variable in
157 /etc/login.defs.
158 -o, --non-unique
160 allows the creation of an account with an already existing UID.
161 This option is only valid in combination with the -u option. As a
163 user identity serves as key to map between users on one hand and
164 permissions, file ownerships and other aspects that determine the
165 system's behavior on the other hand, more than one login name will
166 access the account of the given UID.
167 -p, --password PASSWORD
169 defines an initial password for the account. PASSWORD is expected
170 to be encrypted, as returned by crypt (3). Within a shell script,
171 this option allows to create efficiently batches of users.
172 Without this option, the new account will be locked and with no
174 password defined, i.e. a single exclamation mark in the respective
175 field of /etc/shadow. This is a state where the user won't be able
176 to access the account or to define a password himself.
177 Note:Avoid this option on the command line because the password (or
179 encrypted password) will be visible by users listing the processes.
180 You should make sure the password respects the system's password
182 policy.
183 -r, --system
185 Create a system account.
186 System users will be created with no aging information in
188 /etc/shadow, and their numeric identifiers are chosen in the
189 SYS_UID_MIN-SYS_UID_MAX range, defined in /etc/login.defs, instead
190 of UID_MIN-UID_MAX (and their GID counterparts for the creation of
191 groups).
192 Note that useradd will not create a home directory for such a user,
194 regardless of the default setting in /etc/login.defs (CREATE_HOME).
195 You have to specify the -m options if you want a home directory for
196 a system account to be created.
197 Note that this option will not update /etc/subuid and /etc/subgid.
199 You have to specify the -F options if you want to update the files
200 for a system account to be created.
201 -R, --root CHROOT_DIR
203 Apply changes in the CHROOT_DIR directory and use the configuration
204 files from the CHROOT_DIR directory. Only absolute paths are
205 supported.
206 -P, --prefix PREFIX_DIR
208 Apply changes to configuration files under the root filesystem
209 found under the directory PREFIX_DIR. This option does not chroot
210 and is intended for preparing a cross-compilation target. Some
211 limitations: NIS and LDAP users/groups are not verified. PAM
212 authentication is using the host files. No SELINUX support.
213 -s, --shell SHELL
215 sets the path to the user's login shell. Without this option, the
216 system will use the SHELL variable specified in
217 /etc/default/useradd, or, if that is as well not set, the field for
218 the login shell in /etc/passwdremains empty.
219 -u, --uid UID
221 The numerical value of the user's ID. This value must be unique,
222 unless the -o option is used. The value must be non-negative. The
223 default is to use the smallest ID value greater than or equal to
224 UID_MIN and greater than every other user.
225 See also the -r option and the UID_MAX description.
227 -U, --user-group
229 Create a group with the same name as the user, and add the user to
230 this group.
231 The default behavior (if the -g, -N, and -U options are not
233 specified) is defined by the USERGROUPS_ENAB variable in
234 /etc/login.defs.
235 -Z, --selinux-user SEUSER
237 defines the SELinux user for the new account. Without this option,
238 a SELinux uses the default user. Note that the shadow system
239 doesn't store the selinux-user, it uses semanage(8) for that.
240 Changing the default values
242 When invoked with only the -D option, useradd will display the current
243 default values. When invoked with -D plus other options, useradd will
244 update the default values for the specified options. Valid
245 default-changing options are:
246 -b, --base-dir BASE_DIR
248 sets the path prefix for a new user's home directory. The user's
249 name will be affixed to the end of BASE_DIR to form the new user's
250 home directory name, if the -d option is not used when creating a
251 new account.
252 This option sets the HOME variable in /etc/default/useradd.
254 -e, --expiredate EXPIRE_DATE
256 sets the date on which newly created user accounts are disabled.
257 This option sets the EXPIRE variable in /etc/default/useradd.
259 -f, --inactive INACTIVE
261 defines the number of days after the password exceeded its maximum
262 age where the user is expected to replace this password. See
263 shadow(5)for more information.
264 This option sets the INACTIVE variable in /etc/default/useradd.
266 -g, --gid GROUP
268 sets the default primary group for newly created users, accepting
269 group names or a numerical group ID. The named group must exist,
270 and the GID must have an existing entry.
271 This option sets the GROUP variable in /etc/default/useradd.
273 -s, --shell SHELL
275 defines the default login shell for new users.
276 This option sets the SHELL variable in /etc/default/useradd.
278
280 The system administrator is responsible for placing the default user
281 files in the /etc/skel/ directory (or any other skeleton directory
282 specified in /etc/default/useradd or on the command line).
283
285 You may not add a user to a NIS or LDAP group. This must be performed
286 on the corresponding server.
287 Similarly, if the username already exists in an external user database
289 such as NIS or LDAP, useradd will deny the user account creation
290 request.
291 Usernames may contain only lower and upper case letters, digits,
293 underscores, or dashes. They can end with a dollar sign. Dashes are not
294 allowed at the beginning of the username. Fully numeric usernames and
295 usernames . or .. are also disallowed. It is not recommended to use
296 usernames beginning with . character as their home directories will be
297 hidden in the ls output.
298 Usernames may only be up to 32 characters long.
300
302 The following configuration variables in /etc/login.defs change the
303 behavior of this tool:
304 CREATE_HOME (boolean)
306 Indicate if a home directory should be created by default for new
307 users.
308 This setting does not apply to system users, and can be overridden
310 on the command line.
311 GID_MAX (number), GID_MIN (number)
313 Range of group IDs used for the creation of regular groups by
314 useradd, groupadd, or newusers.
315 The default value for GID_MIN (resp. GID_MAX) is 1000 (resp.
317 60000).
318 HOME_MODE (number)
320 The mode for new home directories. If not specified, the UMASK is
321 used to create the mode.
322 useradd and newusers use this to set the mode of the home directory
324 they create.
325 LASTLOG_UID_MAX (number)
327 Highest user ID number for which the lastlog entries should be
328 updated. As higher user IDs are usually tracked by remote user
329 identity and authentication services there is no need to create a
330 huge sparse lastlog file for them.
331 No LASTLOG_UID_MAX option present in the configuration means that
333 there is no user ID limit for writing lastlog entries.
334 MAIL_DIR (string)
336 The mail spool directory. This is needed to manipulate the mailbox
337 when its corresponding user account is modified or deleted. If not
338 specified, a compile-time default is used. The parameter
339 CREATE_MAIL_SPOOL in /etc/default/useradd determines whether the
340 mail spool should be created.
341 MAIL_FILE (string)
343 Defines the location of the users mail spool files relatively to
344 their home directory.
345 The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
347 userdel to create, move, or delete the user's mail spool.
348 If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
350 environment variable.
351 MAX_MEMBERS_PER_GROUP (number)
353 Maximum members per group entry. When the maximum is reached, a new
354 group entry (line) is started in /etc/group (with the same name,
355 same password, and same GID).
356 The default value is 0, meaning that there are no limits in the
358 number of members in a group.
359 This feature (split group) permits to limit the length of lines in
361 the group file. This is useful to make sure that lines for NIS
362 groups are not larger than 1024 characters.
363 If you need to enforce such limit, you can use 25.
365 Note: split groups may not be supported by all tools (even in the
367 Shadow toolsuite). You should not use this variable unless you
368 really need it.
369 PASS_MAX_DAYS (number)
371 The maximum number of days a password may be used. If the password
372 is older than this, a password change will be forced. If not
373 specified, -1 will be assumed (which disables the restriction).
374 PASS_MIN_DAYS (number)
376 The minimum number of days allowed between password changes. Any
377 password changes attempted sooner than this will be rejected. If
378 not specified, 0 will be assumed (which disables the restriction).
379 PASS_WARN_AGE (number)
381 The number of days warning given before a password expires. A zero
382 means warning is given only upon the day of expiration, a negative
383 value means no warning is given. If not specified, no warning will
384 be provided.
385 SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
387 If /etc/subuid exists, the commands useradd and newusers (unless
388 the user already have subordinate group IDs) allocate SUB_GID_COUNT
389 unused group IDs from the range SUB_GID_MIN to SUB_GID_MAX for each
390 new user.
391 The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are
393 respectively 100000, 600100000 and 65536.
394 SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
396 If /etc/subuid exists, the commands useradd and newusers (unless
397 the user already have subordinate user IDs) allocate SUB_UID_COUNT
398 unused user IDs from the range SUB_UID_MIN to SUB_UID_MAX for each
399 new user.
400 The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are
402 respectively 100000, 600100000 and 65536.
403 SYS_GID_MAX (number), SYS_GID_MIN (number)
405 Range of group IDs used for the creation of system groups by
406 useradd, groupadd, or newusers.
407 The default value for SYS_GID_MIN (resp. SYS_GID_MAX) is 101
409 (resp. GID_MIN-1).
410 SYS_UID_MAX (number), SYS_UID_MIN (number)
412 Range of user IDs used for the creation of system users by useradd
413 or newusers.
414 The default value for SYS_UID_MIN (resp. SYS_UID_MAX) is 101
416 (resp. UID_MIN-1).
417 UID_MAX (number), UID_MIN (number)
419 Range of user IDs used for the creation of regular users by useradd
420 or newusers.
421 The default value for UID_MIN (resp. UID_MAX) is 1000 (resp.
423 60000).
424 UMASK (number)
426 The file mode creation mask is initialized to this value. If not
427 specified, the mask will be initialized to 022.
428 useradd and newusers use this mask to set the mode of the home
430 directory they create if HOME_MODE is not set.
431 It is also used by login to define users' initial umask. Note that
433 this mask can be overridden by the user's GECOS line (if
434 QUOTAS_ENAB is set) or by the specification of a limit with the K
435 identifier in limits(5).
436 USERGROUPS_ENAB (boolean)
438 Enable setting of the umask group bits to be the same as owner bits
439 (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid
440 is the same as gid, and username is the same as the primary group
441 name.
442 If set to yes, userdel will remove the user's group if it contains
444 no more members, and useradd will create by default a group with
445 the name of the user.
446
448 /etc/passwd
449 User account information.
450 /etc/shadow
452 Secure user account information.
453 /etc/group
455 Group account information.
456 /etc/gshadow
458 Secure group account information.
459 /etc/default/useradd
461 Default values for account creation.
462 /etc/shadow-maint/useradd-pre.d/*, /etc/shadow-maint/useradd-post.d/*
464 Run-part files to execute during user addition. The environment
465 variable ACTION will be populated with useradd and SUBJECT with the
466 username. useradd-pre.d will be executed prior to any user
467 addition. useradd-post.d will execute after user addition. If a
468 script exits non-zero then execution will terminate.
469 /etc/skel/
471 Directory containing default files.
472 /etc/subgid
474 Per user subordinate group IDs.
475 /etc/subuid
477 Per user subordinate user IDs.
478 /etc/login.defs
480 Shadow password suite configuration.
481
483 The useradd command exits with the following values:
484 0
486 success
487 1
489 can't update password file
490 2
492 invalid command syntax
493 3
495 invalid argument to option
496 4
498 UID already in use (and no -o)
499 6
501 specified group doesn't exist
502 9
504 username or group name already in use
505 10
507 can't update group file
508 12
510 can't create home directory
511 14
513 can't update SELinux user mapping
514
516 chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8),
517 groupmod(8), login.defs(5), newusers(8), subgid(5), subuid(5),
518 userdel(8), usermod(8).
519shadow-utils 4.12.3 11/29/2022 USERADD(8)