MAN page from RedHat 6.X shadow-utils-980403-12.i386.rpm


Section: Maintenance Commands (8)


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


[-m [-kskeleton_dir] | -M][-sshell]
[-uuid [-o]][-n][-r]login
-D[-g default_group][-b default_home]
[-f default_inactive][-e default_expire_date]
[-s default_shell]



Creating New Users

When invoked without the -D option, the useradd commandcreates a new user account using the values specified on thecommand 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, dependingon the command line options.The version provided with Red Hat Linux will create a group for each user added to the system, unless -n option is given.The options which apply to the useradd command are
-c comment
The new user's password file comment field.
-d home_dir
The new user will be created using home_dir as the value forthe user's login directory.The default is to append the login name to default_homeand use that as the login directory name.
-e expire_date
The date on which the user account will be disabled.The date is specified in the format MM/DD/YY.
-f inactive_days
The number of days after a password expires until the accountis permanently disabled.A value of 0 disables the account as soon as the password hasexpired, and a value of -1 disables the feature.The default value is -1.
-g initial_group
The group name or number of the user's initial login group.The group name must exist. A group number must refer to analready existing group.The default group number is 1.
-G group,[...]
A list of supplementary groups which the user is also a memberof.Each group is separated from the next by a comma, with nointervening whitespace.The groups are subject to the same restrictions as the groupgiven with the -g option.The default is for the user to belong only to the initial group.
The user's home directory will be created if it does not exist.The files contained in skeleton_dir will be copied to thehome directory if the -k option is used, otherwise thefiles contained in /etc/skel will be used instead.Any directories contained in skeleton_dir or /etc/skelwill be created in the user's home directory as well.The -k option is only valid in conjunction with the -moption.The default is to not create the directory and to not copy anyfiles.
The user home directory will not be created, even if the system wide settings from /etc/login.defs is to create home dirs.
A group having the same name as the user being added to the systemwill be created by default. This option will turn off this Red HatLinux specific behavior.
This flag is used to create a system account. That is, an user with anUID lower than value of UID_MIN defined in /etc/login.defs. Notethat useradd will not create a home directory for such an user,regardless of the default setting in /etc/login.defs.You have to specify -m option if you want a home directory for a system account to be created.This is an option added by Red Hat.
-s shell
The name of the user's login shell.The default is to leave this field blank, which causes the systemto select the default login shell.
-u uid
The numerical value of the user's ID.This value must be unique, unless the -o option is used.The value must be non-negative.The default is to use the smallest ID value greater than 99 andgreater than every other user.Values between 0 and 99 are typically reserved for system accounts.

Changing the default values

When invoked with the -D option, useradd will eitherdisplay the current default values, or update the default valuesfrom the command line.The valid options are
-b default_home
The initial path prefix for a new user's home directory.The user's name will be affixed to the end of default_hometo create the new directory name if the -d option is notused when creating a new account.
-e default_expire_date
The date on which the user account is disabled.
-f default_inactive
The number of days after a password has expired before theaccount will be disabled.
-g default_group
The group name or ID for a new user's initial group.The named group must exist, and a numerical group ID must havean existing entry .
-s default_shell
The name of the new user's login shell.The named program will be used for all future new user accounts.

If no options are specified, useradd displays the currentdefault values. 


The system administrator is responsible for placing the defaultuser files in the /etc/skel directory.
This version of useradd was modified by Red Hat to suit Red Hat user/group convention. 


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


/etc/passwd - user account information
/etc/shadow - secure user account information
/etc/group - group information
/etc/default/useradd - default information
/etc/login.defs - system-wide settings
/etc/skel - directory containing default files 




Julianne Frances Haugh (



Creating New Users
Changing the default values

This document was created byman2html,using the manual pages.