MAN page from OpenSuSE shadow-4.6-lp151.2.3.2.x86_64.rpm


Section: System Management Commands (8)
Updated: 04/29/2018


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


useradd [options] LOGIN
useradd -D
useradd -D [options]


When invoked without the-Doption, theuseraddcommand creates a new user account using the values specified on the command line plus the default values from the system. Depending on command line options, theuseraddcommand will update system files and may also create the new user's home directory and copy initial files.

By default, a group will also be created for the new user (see-g,-N,-U, andUSERGROUPS_ENAB). 


The options which apply to theuseraddcommand are:

-b, --base-dir BASE_DIR

The default base directory for the system if-d HOME_DIRis not specified.BASE_DIRis concatenated with the account name to define the home directory. If the-moption is not used,BASE_DIRmust exist.

If this option is not specified,useraddwill use the base directory specified by theHOMEvariable in/etc/default/useradd, or/homeby default.

-c, --comment COMMENT

Any text string. It is generally a short description of the login, and is currently used as the field for the user's full name.

-d, --home-dir HOME_DIR

The new user will be created usingHOME_DIRas the value for the user's login directory. The default is to append theLOGINname toBASE_DIRand use that as the login directory name. The directoryHOME_DIRdoes not have to exist but will not be created if it is missing.

-D, --defaults

See below, the subsection "Changing the default values".

-e, --expiredate EXPIRE_DATE

The date on which the user account will be disabled. The date is specified in the formatYYYY-MM-DD.

If not specified,useraddwill use the default expiry date specified by theEXPIREvariable in/etc/default/useradd, or an empty string (no expiry) by default.

-f, --inactive INACTIVE

The number of days after a password expires until the account is permanently disabled. A value of 0 disables the account as soon as the password has expired, and a value of -1 disables the feature.

If not specified,useraddwill use the default inactivity period specified by theINACTIVEvariable in/etc/default/useradd, or -1 by default.

-g, --gid GROUP

The group name or number of the user's initial login group. The group name must exist. A group number must refer to an already existing group.

If not specified, the behavior ofuseraddwill depend on theUSERGROUPS_ENABvariable in/etc/login.defs. If this variable is set toyes(or-U/--user-groupis specified on the command line), a group will be created for the user, with the same name as her loginname. If the variable is set tono(or-N/--no-user-groupis specified on the command line), useradd will set the primary group of the new user to the value specified by theGROUPvariable in/etc/default/useradd, or 100 by default.

-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]

A list of supplementary groups which the user is also a member of. Each group is separated from the next by a comma, with no intervening whitespace. The groups are subject to the same restrictions as the group given with the-goption. The default is for the user to belong only to the initial group.

-h, --help

Display help message and exit.

-k, --skel SKEL_DIR

The skeleton directory, which contains files and directories to be copied in the user's home directory, when the home directory is created byuseradd.

This option is only valid if the-m(or--create-home) option is specified.

If this option is not set, the skeleton directory is defined by theSKELvariable in/etc/default/useraddor, by default,/etc/skel.

If possible, the ACLs and extended attributes are copied.

-K, --key KEY=VALUE

Overrides/etc/login.defsdefaults (UID_MIN,UID_MAX,UMASK,PASS_MAX_DAYSand others).

Example:-K PASS_MAX_DAYS=-1can be used when creating system account to turn off password aging, even though system account has no password at all. Multiple-Koptions can be specified, e.g.:-K UID_MIN=100 -K UID_MAX=499

-l, --no-log-init

Do not add the user to the lastlog and faillog databases.

By default, the user's entries in the lastlog and faillog databases are reset to avoid reusing the entry from a previously deleted user.

-m, --create-home

Create the user's home directory if it does not exist. The files and directories contained in the skeleton directory (which can be defined with the-koption) will be copied to the home directory.

By default, if this option is not specified andCREATE_HOMEis not enabled, no home directories are created.

-M, --no-create-home

Do no create the user's home directory, even if the system wide setting from/etc/login.defs(CREATE_HOME) is set toyes.

-N, --no-user-group

Do not create a group with the same name as the user, but add the user to the group specified by the-goption or by theGROUPvariable in/etc/default/useradd.

The default behavior (if the-g,-N, and-Uoptions are not specified) is defined by theUSERGROUPS_ENABvariable in/etc/login.defs.

-o, --non-unique

Allow the creation of a user account with a duplicate (non-unique) UID.

This option is only valid in combination with the-uoption.

-p, --password PASSWORD

The encrypted password, as returned bycrypt(3). The default is to disable the password.

Note:This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.

You should make sure the password respects the system's password policy.

-r, --system

Create a system account.

System users will be created with no aging information in/etc/shadow, and their numeric identifiers are chosen in theSYS_UID_MIN-SYS_UID_MAXrange, defined in/etc/login.defs, instead ofUID_MIN-UID_MAX(and theirGIDcounterparts for the creation of groups).

Note thatuseraddwill not create a home directory for such a user, regardless of the default setting in/etc/login.defs(CREATE_HOME). You have to specify the-moptions if you want a home directory for a system account to be created.

-R, --root CHROOT_DIR

Apply changes in theCHROOT_DIRdirectory and use the configuration files from theCHROOT_DIRdirectory.

-P, --prefix PREFIX_DIR

Apply changes in thePREFIX_DIRdirectory and use the configuration files from thePREFIX_DIRdirectory. This option does not chroot and is intended for preparing a cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified. PAM authentication is using the host files. No SELINUX support.

-s, --shell SHELL

The name of the user's login shell. The default is to leave this field blank, which causes the system to select the default login shell specified by theSHELLvariable in/etc/default/useradd, or an empty string by default.

-u, --uid UID

The numerical value of the user's ID. This value must be unique, unless the-ooption is used. The value must be non-negative. The default is to use the smallest ID value greater than or equal toUID_MINand greater than every other user.

See also the-roption and theUID_MAXdescription.

-U, --user-group

Create a group with the same name as the user, and add the user to this group.

The default behavior (if the-g,-N, and-Uoptions are not specified) is defined by theUSERGROUPS_ENABvariable in/etc/login.defs.

-Z, --selinux-user SEUSER

The SELinux user for the user's login. The default is to leave this field blank, which causes the system to select the default SELinux user.

Changing the default values

When invoked with only the-Doption,useraddwill display the current default values. When invoked with-Dplus other options,useraddwill update the default values for the specified options. Valid default-changing options are:

-b, --base-dir BASE_DIR

The path prefix for a new user's home directory. The user's name will be affixed to the end ofBASE_DIRto form the new user's home directory name, if the-doption is not used when creating a new account.

This option sets theHOMEvariable in/etc/default/useradd.

-e, --expiredate EXPIRE_DATE

The date on which the user account is disabled.

This option sets theEXPIREvariable in/etc/default/useradd.

-f, --inactive INACTIVE

The number of days after a password has expired before the account will be disabled.

This option sets theINACTIVEvariable in/etc/default/useradd.

-g, --gid GROUP

The group name or ID for a new user's initial group (when the-N/--no-user-groupis used or when theUSERGROUPS_ENABvariable is set tonoin/etc/login.defs). The named group must exist, and a numerical group ID must have an existing entry.

This option sets theGROUPvariable in/etc/default/useradd.

-s, --shell SHELL

The name of a new user's login shell.

This option sets theSHELLvariable in/etc/default/useradd.



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


You may not add a user to a NIS or LDAP group. This must be performed on the corresponding server.

Similarly, if the username already exists in an external user database such as NIS or LDAP,useraddwill deny the user account creation request.

Usernames must start with a lower case letter or an underscore, followed by lower case letters, digits, underscores, or dashes. They can end with a dollar sign. In regular expression terms: [a-z_][a-z0-9_-]*[$]?

Usernames may only be up to 32 characters long. 


The following configuration variables in/etc/login.defschange the behavior of this tool:

CREATE_HOME (boolean)

Indicate if a home directory should be created by default for new users.

This setting does not apply to system users, and can be overridden on the command line.

GID_MAX (number), GID_MIN (number)

Range of group IDs used for the creation of regular groups byuseradd,groupadd, ornewusers.

The default value forGID_MIN(resp.GID_MAX) is 1000 (resp. 60000).

MAIL_DIR (string)

The mail spool directory. This is needed to manipulate the mailbox when its corresponding user account is modified or deleted. If not specified, a compile-time default is used.

MAIL_FILE (string)

Defines the location of the users mail spool files relatively to their home directory.

TheMAIL_DIRandMAIL_FILEvariables are used byuseradd,usermod, anduserdelto create, move, or delete the user's mail spool.

IfMAIL_CHECK_ENABis set toyes, they are also used to define theMAILenvironment variable.


Maximum members per group entry. When the maximum is reached, a new group entry (line) is started in/etc/group(with the same name, same password, and same GID).

The default value is 0, meaning that there are no limits in the number of members in a group.

This feature (split group) permits to limit the length of lines in the group file. This is useful to make sure that lines for NIS groups are not larger than 1024 characters.

If you need to enforce such limit, you can use 25.

Note: split groups may not be supported by all tools (even in the Shadow toolsuite). You should not use this variable unless you really need it.

PASS_MAX_DAYS (number)

The maximum number of days a password may be used. If the password is older than this, a password change will be forced. If not specified, -1 will be assumed (which disables the restriction).

PASS_MIN_DAYS (number)

The minimum number of days allowed between password changes. Any password changes attempted sooner than this will be rejected. If not specified, -1 will be assumed (which disables the restriction).

PASS_WARN_AGE (number)

The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a negative value means no warning is given. If not specified, no warning will be provided.

SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)

If/etc/subuidexists, the commandsuseraddandnewusers(unless the user already have subordinate group IDs) allocateSUB_GID_COUNTunused group IDs from the rangeSUB_GID_MINtoSUB_GID_MAXfor each new user.

The default values forSUB_GID_MIN,SUB_GID_MAX,SUB_GID_COUNTare respectively 100000, 600100000 and 10000.

SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)

If/etc/subuidexists, the commandsuseraddandnewusers(unless the user already have subordinate user IDs) allocateSUB_UID_COUNTunused user IDs from the rangeSUB_UID_MINtoSUB_UID_MAXfor each new user.

The default values forSUB_UID_MIN,SUB_UID_MAX,SUB_UID_COUNTare respectively 100000, 600100000 and 10000.

SYS_GID_MAX (number), SYS_GID_MIN (number)

Range of group IDs used for the creation of system groups byuseradd,groupadd, ornewusers.

The default value forSYS_GID_MIN(resp.SYS_GID_MAX) is 101 (resp.GID_MIN-1).

SYS_UID_MAX (number), SYS_UID_MIN (number)

Range of user IDs used for the creation of system users byuseraddornewusers.

The default value forSYS_UID_MIN(resp.SYS_UID_MAX) is 101 (resp.UID_MIN-1).

UID_MAX (number), UID_MIN (number)

Range of user IDs used for the creation of regular users byuseraddornewusers.

The default value forUID_MIN(resp.UID_MAX) is 1000 (resp. 60000).

UMASK (number)

The file mode creation mask is initialized to this value. If not specified, the mask will be initialized to 022.

useraddandnewusersuse this mask to set the mode of the home directory they create

It is also used byloginto define users' initial umask. Note that this mask can be overridden by the user's GECOS line (ifQUOTAS_ENABis set) or by the specification of a limit with theKidentifier inlimits(5).


Enable setting of the umask group bits to be the same as owner bits (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid is the same as gid, and username is the same as the primary group name.

If set toyes,userdelwill remove the user's group if it contains no more members, anduseraddwill create by default a group with the name of the user.




User account information.


Secure user account information.


Group account information.


Secure group account information.


Default values for account creation.


Directory containing default files.


Per user subordinate group IDs.


Per user subordinate user IDs.


Shadow password suite configuration.


Theuseraddcommand exits with the following values:




can't update password file


invalid command syntax


invalid argument to option


UID already in use (and no-o)


specified group doesn't exist


username already in use


can't update group file


can't create home directory


can't update SELinux user mapping


chfn(1),chsh(1),passwd(1),crypt(3),groupadd(8),groupdel(8),groupmod(8),login.defs(5),newusers(8),subgid(5), subuid(5),userdel(8),usermod(8).



Changing the default values

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