Command	Description
useradd	Adds accounts to the system.
usermod	Modifies account attributes.
userdel	Deletes accounts from the system.
groupadd	Adds groups to the system.
groupmod	Modifies group attributes.
groupdel	Removes groups from the system.

Option	Description
-g GID	The numerical value of the group's ID.
-o	This option permits to add group with non-unique GID
-r	This flag instructs groupadd to add a system account
-f	This option causes to just exit with success status if the specified group already exists. With -g, if specified GID already exists, other (unique) GID is chosen
groupname	Actaul group name to be created.

Option	Description
-d homedir	Specifies home directory for the account.
-g groupname	Specifies a group account for this account.
-m	Creates the home directory if it doesn't exist.
-s shell	Specifies the default shell for this account.
-u userid	You can specify a user id for this account.
accountname	Actual account name to be created

 groupadd [-g gid [-o]] [-r] [-f] groupname

						

$ groupadd developers

						
Modify a Group:

$ groupmod -n new_modified_group_name old_group_name

						

$ groupmod -n developer developer_2

						

$ groupmod -g 545 developer

						
Delete a Group:

$ groupdel developer

						
Create an Account

useradd -d homedir -g groupname -m -s shell -u userid accountname

						

$ useradd -d /home/mcmohd -g developers -s /bin/ksh mcmohd

						

$ passwd mcmohd20
Changing password for user mcmohd20.
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully.

						
Modify an Account:

$ usermod -d /home/mcmohd20 -m -l mcmohd mcmohd20

						
Delete an Account:

$ userdel -r mcmohd20