1USERADD(8)                System Management Commands                USERADD(8)
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4

NAME

6       useradd - create a new user or update default new user information
7

SYNOPSIS

9       useradd [options] LOGIN
10
11       useradd -D
12
13       useradd -D [options]
14

DESCRIPTION

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
22       By default, a group will also be created for the new user (see -g, -N,
23       -U, and USERGROUPS_ENAB).
24

OPTIONS

26       The options which apply to the useradd command are:
27
28       --badname
29           Allow names that do not conform to standards.
30
31       -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. If the -m option is not used, BASE_DIR
35           must exist.
36
37           If this option is not specified, useradd will use the base
38           directory specified by the HOME variable in /etc/default/useradd,
39           or /home by default.
40
41       -c, --comment COMMENT
42           Any text string. It is generally a short description of the login,
43           and is currently used as the field for the user's full name.
44
45       -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
52       -D, --defaults
53           See below, the subsection "Changing the default values".
54
55       -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
59           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
63       -f, --inactive INACTIVE
64           The number of days after a password expires until the account is
65           permanently disabled. A value of 0 disables the account as soon as
66           the password has expired, and a value of -1 disables the feature.
67
68           If not specified, useradd will use the default inactivity period
69           specified by the INACTIVE variable in /etc/default/useradd, or -1
70           by default.
71
72       -g, --gid GROUP
73           The group name or number of the user's initial login group. The
74           group name must exist. A group number must refer to an already
75           existing group.
76
77           If not specified, the behavior of useradd will depend on the
78           USERGROUPS_ENAB variable in /etc/login.defs. If this variable is
79           set to yes (or -U/--user-group is specified on the command line), a
80           group will be created for the user, with the same name as her
81           loginname. If the variable is set to no (or -N/--no-user-group is
82           specified on the command line), useradd will set the primary group
83           of the new user to the value specified by the GROUP variable in
84           /etc/default/useradd, or 100 by default.
85
86       -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
87           A list of supplementary groups which the user is also a member of.
88           Each group is separated from the next by a comma, with no
89           intervening whitespace. The groups are subject to the same
90           restrictions as the group given with the -g option. The default is
91           for the user to belong only to the initial group.
92
93       -h, --help
94           Display help message and exit.
95
96       -k, --skel SKEL_DIR
97           The skeleton directory, which contains files and directories to be
98           copied in the user's home directory, when the home directory is
99           created by useradd.
100
101           This option is only valid if the -m (or --create-home) option is
102           specified.
103
104           If this option is not set, the skeleton directory is defined by the
105           SKEL variable in /etc/default/useradd or, by default, /etc/skel.
106
107           If possible, the ACLs and extended attributes are copied.
108
109       -K, --key KEY=VALUE
110           Overrides /etc/login.defs defaults (UID_MIN, UID_MAX, UMASK,
111           PASS_MAX_DAYS and others).
112
113           Example: -K PASS_MAX_DAYS=-1 can be used when creating system
114           account to turn off password aging, even though system account has
115           no password at all. Multiple -K options can be specified, e.g.:
116           -K UID_MIN=100  -K UID_MAX=499
117
118       -l, --no-log-init
119           Do not add the user to the lastlog and faillog databases.
120
121           By default, the user's entries in the lastlog and faillog databases
122           are reset to avoid reusing the entry from a previously deleted
123           user.
124
125       -m, --create-home
126           Create the user's home directory if it does not exist. The files
127           and directories contained in the skeleton directory (which can be
128           defined with the -k option) will be copied to the home directory.
129
130           By default, if this option is not specified and CREATE_HOME is not
131           enabled, no home directories are created.
132
133           The directory where the user's home directory is created must exist
134           and have proper SELinux context and permissions. Otherwise the
135           user's home directory cannot be created or accessed.
136
137       -M, --no-create-home
138           Do no create the user's home directory, even if the system wide
139           setting from /etc/login.defs (CREATE_HOME) is set to yes.
140
141       -N, --no-user-group
142           Do not create a group with the same name as the user, but add the
143           user to the group specified by the -g option or by the GROUP
144           variable in /etc/default/useradd.
145
146           The default behavior (if the -g, -N, and -U options are not
147           specified) is defined by the USERGROUPS_ENAB variable in
148           /etc/login.defs.
149
150       -o, --non-unique
151           Allow the creation of a user account with a duplicate (non-unique)
152           UID.
153
154           This option is only valid in combination with the -u option.
155
156       -p, --password PASSWORD
157           The encrypted password, as returned by crypt(3). The default is to
158           disable the password.
159
160           Note: This option is not recommended because the password (or
161           encrypted password) will be visible by users listing the processes.
162
163           You should make sure the password respects the system's password
164           policy.
165
166       -r, --system
167           Create a system account.
168
169           System users will be created with no aging information in
170           /etc/shadow, and their numeric identifiers are chosen in the
171           SYS_UID_MIN-SYS_UID_MAX range, defined in /etc/login.defs, instead
172           of UID_MIN-UID_MAX (and their GID counterparts for the creation of
173           groups).
174
175           Note that useradd will not create a home directory for such a user,
176           regardless of the default setting in /etc/login.defs (CREATE_HOME).
177           You have to specify the -m options if you want a home directory for
178           a system account to be created.
179
180       -R, --root CHROOT_DIR
181           Apply changes in the CHROOT_DIR directory and use the configuration
182           files from the CHROOT_DIR directory.
183
184       -P, --prefix PREFIX_DIR
185           Apply changes in the PREFIX_DIR directory and use the configuration
186           files from the PREFIX_DIR directory. This option does not chroot
187           and is intended for preparing a cross-compilation target. Some
188           limitations: NIS and LDAP users/groups are not verified. PAM
189           authentication is using the host files. No SELINUX support.
190
191       -s, --shell SHELL
192           The name of the user's login shell. The default is to leave this
193           field blank, which causes the system to select the default login
194           shell specified by the SHELL variable in /etc/default/useradd, or
195           an empty string by default.
196
197       -u, --uid UID
198           The numerical value of the user's ID. This value must be unique,
199           unless the -o option is used. The value must be non-negative. The
200           default is to use the smallest ID value greater than or equal to
201           UID_MIN and greater than every other user.
202
203           See also the -r option and the UID_MAX description.
204
205       -U, --user-group
206           Create a group with the same name as the user, and add the user to
207           this group.
208
209           The default behavior (if the -g, -N, and -U options are not
210           specified) is defined by the USERGROUPS_ENAB variable in
211           /etc/login.defs.
212
213       -Z, --selinux-user SEUSER
214           The SELinux user for the user's login. The default is to leave this
215           field blank, which causes the system to select the default SELinux
216           user.
217
218   Changing the default values
219       When invoked with only the -D option, useradd will display the current
220       default values. When invoked with -D plus other options, useradd will
221       update the default values for the specified options. Valid
222       default-changing options are:
223
224       -b, --base-dir BASE_DIR
225           The path prefix for a new user's home directory. The user's name
226           will be affixed to the end of BASE_DIR to form the new user's home
227           directory name, if the -d option is not used when creating a new
228           account.
229
230           This option sets the HOME variable in /etc/default/useradd.
231
232       -e, --expiredate EXPIRE_DATE
233           The date on which the user account is disabled.
234
235           This option sets the EXPIRE variable in /etc/default/useradd.
236
237       -f, --inactive INACTIVE
238           The number of days after a password has expired before the account
239           will be disabled.
240
241           This option sets the INACTIVE variable in /etc/default/useradd.
242
243       -g, --gid GROUP
244           The group name or ID for a new user's initial group (when the
245           -N/--no-user-group is used or when the USERGROUPS_ENAB variable is
246           set to no in /etc/login.defs). The named group must exist, and a
247           numerical group ID must have an existing entry.
248
249           This option sets the GROUP variable in /etc/default/useradd.
250
251       -s, --shell SHELL
252           The name of a new user's login shell.
253
254           This option sets the SHELL variable in /etc/default/useradd.
255

NOTES

257       The system administrator is responsible for placing the default user
258       files in the /etc/skel/ directory (or any other skeleton directory
259       specified in /etc/default/useradd or on the command line).
260

CAVEATS

262       You may not add a user to a NIS or LDAP group. This must be performed
263       on the corresponding server.
264
265       Similarly, if the username already exists in an external user database
266       such as NIS or LDAP, useradd will deny the user account creation
267       request.
268
269       Usernames may contain only lower and upper case letters, digits,
270       underscores, or dashes. They can end with a dollar sign. Dashes are not
271       allowed at the beginning of the username. Fully numeric usernames and
272       usernames . or .. are also disallowed. It is not recommended to use
273       usernames beginning with . character as their home directories will be
274       hidden in the ls output.
275
276       Usernames may only be up to 32 characters long.
277

CONFIGURATION

279       The following configuration variables in /etc/login.defs change the
280       behavior of this tool:
281
282       CREATE_HOME (boolean)
283           Indicate if a home directory should be created by default for new
284           users.
285
286           This setting does not apply to system users, and can be overridden
287           on the command line.
288
289       GID_MAX (number), GID_MIN (number)
290           Range of group IDs used for the creation of regular groups by
291           useradd, groupadd, or newusers.
292
293           The default value for GID_MIN (resp.  GID_MAX) is 1000 (resp.
294           60000).
295
296       HOME_MODE (number)
297           The mode for new home directories. If not specified, the UMASK is
298           used to create the mode.
299
300           useradd and newusers use this to set the mode of the home directory
301           they create.
302
303       LASTLOG_UID_MAX (number)
304           Highest user ID number for which the lastlog entries should be
305           updated. As higher user IDs are usually tracked by remote user
306           identity and authentication services there is no need to create a
307           huge sparse lastlog file for them.
308
309           No LASTLOG_UID_MAX option present in the configuration means that
310           there is no user ID limit for writing lastlog entries.
311
312       MAIL_DIR (string)
313           The mail spool directory. This is needed to manipulate the mailbox
314           when its corresponding user account is modified or deleted. If not
315           specified, a compile-time default is used.
316
317       MAIL_FILE (string)
318           Defines the location of the users mail spool files relatively to
319           their home directory.
320
321       The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
322       userdel to create, move, or delete the user's mail spool.
323
324       If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
325       environment variable.
326
327       MAX_MEMBERS_PER_GROUP (number)
328           Maximum members per group entry. When the maximum is reached, a new
329           group entry (line) is started in /etc/group (with the same name,
330           same password, and same GID).
331
332           The default value is 0, meaning that there are no limits in the
333           number of members in a group.
334
335           This feature (split group) permits to limit the length of lines in
336           the group file. This is useful to make sure that lines for NIS
337           groups are not larger than 1024 characters.
338
339           If you need to enforce such limit, you can use 25.
340
341           Note: split groups may not be supported by all tools (even in the
342           Shadow toolsuite). You should not use this variable unless you
343           really need it.
344
345       PASS_MAX_DAYS (number)
346           The maximum number of days a password may be used. If the password
347           is older than this, a password change will be forced. If not
348           specified, -1 will be assumed (which disables the restriction).
349
350       PASS_MIN_DAYS (number)
351           The minimum number of days allowed between password changes. Any
352           password changes attempted sooner than this will be rejected. If
353           not specified, -1 will be assumed (which disables the restriction).
354
355       PASS_WARN_AGE (number)
356           The number of days warning given before a password expires. A zero
357           means warning is given only upon the day of expiration, a negative
358           value means no warning is given. If not specified, no warning will
359           be provided.
360
361       SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
362           If /etc/subuid exists, the commands useradd and newusers (unless
363           the user already have subordinate group IDs) allocate SUB_GID_COUNT
364           unused group IDs from the range SUB_GID_MIN to SUB_GID_MAX for each
365           new user.
366
367           The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are
368           respectively 100000, 600100000 and 65536.
369
370       SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
371           If /etc/subuid exists, the commands useradd and newusers (unless
372           the user already have subordinate user IDs) allocate SUB_UID_COUNT
373           unused user IDs from the range SUB_UID_MIN to SUB_UID_MAX for each
374           new user.
375
376           The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are
377           respectively 100000, 600100000 and 65536.
378
379       SYS_GID_MAX (number), SYS_GID_MIN (number)
380           Range of group IDs used for the creation of system groups by
381           useradd, groupadd, or newusers.
382
383           The default value for SYS_GID_MIN (resp.  SYS_GID_MAX) is 101
384           (resp.  GID_MIN-1).
385
386       SYS_UID_MAX (number), SYS_UID_MIN (number)
387           Range of user IDs used for the creation of system users by useradd
388           or newusers.
389
390           The default value for SYS_UID_MIN (resp.  SYS_UID_MAX) is 101
391           (resp.  UID_MIN-1).
392
393       UID_MAX (number), UID_MIN (number)
394           Range of user IDs used for the creation of regular users by useradd
395           or newusers.
396
397           The default value for UID_MIN (resp.  UID_MAX) is 1000 (resp.
398           60000).
399
400       UMASK (number)
401           The file mode creation mask is initialized to this value. If not
402           specified, the mask will be initialized to 022.
403
404           useradd and newusers use this mask to set the mode of the home
405           directory they create if HOME_MODE is not set.
406
407           It is also used by login to define users' initial umask. Note that
408           this mask can be overridden by the user's GECOS line (if
409           QUOTAS_ENAB is set) or by the specification of a limit with the K
410           identifier in limits(5).
411
412       USERGROUPS_ENAB (boolean)
413           Enable setting of the umask group bits to be the same as owner bits
414           (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid
415           is the same as gid, and username is the same as the primary group
416           name.
417
418           If set to yes, userdel will remove the user's group if it contains
419           no more members, and useradd will create by default a group with
420           the name of the user.
421

FILES

423       /etc/passwd
424           User account information.
425
426       /etc/shadow
427           Secure user account information.
428
429       /etc/group
430           Group account information.
431
432       /etc/gshadow
433           Secure group account information.
434
435       /etc/default/useradd
436           Default values for account creation.
437
438       /etc/skel/
439           Directory containing default files.
440
441       /etc/subgid
442           Per user subordinate group IDs.
443
444       /etc/subuid
445           Per user subordinate user IDs.
446
447       /etc/login.defs
448           Shadow password suite configuration.
449

EXIT VALUES

451       The useradd command exits with the following values:
452
453       0
454           success
455
456       1
457           can't update password file
458
459       2
460           invalid command syntax
461
462       3
463           invalid argument to option
464
465       4
466           UID already in use (and no -o)
467
468       6
469           specified group doesn't exist
470
471       9
472           username already in use
473
474       10
475           can't update group file
476
477       12
478           can't create home directory
479
480       14
481           can't update SELinux user mapping
482

SEE ALSO

484       chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8),
485       groupmod(8), login.defs(5), newusers(8), subgid(5), subuid(5),
486       userdel(8), usermod(8).
487
488
489
490shadow-utils 4.8.1                11/16/2020                        USERADD(8)
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