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


useradd [-c comment] [-d home_dir] [-g initial_group] [-G group...] [-m [-k skeleton_dir]] [-p passwd] [-r] [-s shell] [-u uid [-o]] login
useradd -D [-g default_group] [-b default_home] [-s default_shell]


When invoked without the -D option, and with appropriate privilege, useradd creates a new user account using the values specified on the command line and the default values from the system. The new user account will be entered into the system files as needed, the home directory will be created, and initial files copied, depending on the command line options. If the group named group does not exist, or the user names login already exists, or the user ID uid is already in use and no -o option is specified, then useradd shall issue a diagnostic message and exit with a non-zero exit status.

When invoked with the -D option, useradd will either display the current default values, or, with appropriate privilege, update the default values from the command line. If no options are specified, useradd displays the current default values.

The useradd command is a system administration utility, see Path For System Administration Utilities.

Standard Options

-c comment 

specifies the new user's password file comment field value.

-d home_dir 

creates the new user using home_dir as the value for the user's login directory. The default is to append the login name to default_home and use that as the login directory name.

-g initial_group 

specifies the group name or number of the user's initial login group. The group name shall exist. A group number shall refer to an already existing group. If -g is not specified, the implementation will follow the normal user default for that system. This may create a new group or choose a default group that normal users are placed in. Applications which require control of the groups into which a user is placed should specify -g.

-G group[,...] 

specifies 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 -g option. The default is for the user to belong only to the initial group.

-m [-k skeleton_dir] 

specifies the user's home directory will be created if it does not exist. The files contained in skeleton_dir will be copied to the home directory if the -k option is used, otherwise the files contained in /etc/skel will be used instead. Any directories contained in skeleton_dir or /etc/skel will be created in the user's home directory as well. The -k option is only valid in conjunction with the -m option. The default is to not create the directory and to not copy any files.

-p passwd 

is the encrypted password, as returned by crypt(). The default is to disable the account.


creates a system account, that is, a user with a User ID in the range reserved for system account users. If there is not a User ID free in the reserved range the command will fail.

-s shell 

specifies 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.

-u uid [-o] 

specifies the numerical value of the user's ID. This value shall be unique, unless the -o option is used. The value shall be non-negative. The default is the smallest ID value greater than 499 which is not yet used.

Change Default Options

-b default_home 

specifies the initial path prefix for a new user's home directory. The user's name will be affixed to the end of default_home to create the new directory name if the -d option is not used when creating a new account.

-g default_group 

specifies the group name or ID for a new user's initial group. The named group shall exist, and a numerical group ID shall have an existing entry.

-s default_shell 

specifies the name of the new user's login shell. The named program will be used for all future new user accounts.

-c comment 

specifies the new user's password file comment field value.

Application Usage

The -D option will typically be used by system administration packages. Most applications should not change defaults which will affect other applications and users.