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Thursday, 14 September 2017

useradd Linux Command


useradd [options] [user]
System administration command. Create new user accounts or update default account information. Unless invoked with the -D option, user must be given. useradd will create new entries in system files. Home directories and initial files may also be created as needed.


-c comment
Comment field.

-d dir
Home directory. The default is to use user as the directory name under the home directory specified with the -D option.

-e date
Account expiration date. Use the format MM/DD/YYYY. Two-digit year fields are also accepted. The value is stored as the number of days since January 1, 1970. This option requires the use of shadow passwords.

-f days
Permanently disable account this many days after the password has expired. A value of -1 disables this feature. This option requires the use of shadow passwords.

-g group
Initial group name or ID number. If a different default group has not been specified using the -D option, the default group is 1.

-G groups
Supplementary groups given by name or number in a comma-separated list with no whitespace.

-k [dir]
Copy default files to the user's home directory. Meaningful only when used with the -m option. Default files are copied from /etc/skel/ unless an alternate dir is specified.

Make user's home directory if it does not exist. The default is not to make the home directory.

Do not create a home directory for the user, even if the system default in /etc/login.defs is to create one.

Red Hat-specific option. Turn off the Red Hat default that creates a group with the same name as the username and puts the user in that group.

Override. Accept a nonunique uid with the -u option. (Probably a bad idea.)

-p passwd
The encrypted password, as returned by crypt(3).

Red Hat-specific option. Create a system account with a non-expiring password and a UID lower than the minimum defined in /etc/login.defs. Do not create a home directory for the account unless -m is also specified.

-s shell
Login shell.

-u uid
Numerical user ID. The value must be unique unless the -o option is used. The default value is the smallest ID value greater than 99 and greater than every other uid.

-D [options]
Set or display defaults. If options are specified, set them. If no options are specified, display current defaults. The options are:

-b dir
Home directory prefix to be used in creating home directories. If the -d option is not used when creating an account, the user name will be appended to dir.

-e date
Expire date. Requires the use of shadow passwords.

-f days
Number of days after a password expires to disable an account. Requires the use of shadow passwords.

-g group
Initial group name or ID number.

-s shell
Default login shell.
Annamalai Thangaraj

Annamalai is working as Technical Lead in Leading Telecom company with 5+ years experience in Identity and Access Management , Telecom and Networks, BigData, Java, Spring, Struts, Hibernate, AngularJS, and Enterprise Web Application Development.

Website: Java Tutorials Corner

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Item Reviewed: useradd Linux Command Rating: 5 Reviewed By: Annamalai Thangaraj