34,333
edits
Changes
no edit summary
Linux is a multi-user operating system. This means that more than one user can be actively logged and using the system at any one time. Obviously, it makes sense for each user to have their own user account and home directory, and for different users to have different privileges.
Users are further divided into groups for the purposes of easier administration and those groups can have different levels of privileges. For example, you may have a group of users who work in the Accounting department. In such an environment you may wish to create an ''accounts'' group and assign all the the Accounting department to that group.
In this chapter we will cover the steps to add, remove and manage users and groups on an Ubuntu Linux system.
== Adding a User to an Ubuntu Linux System ==
There are two methods for adding new users to a system, one way is using the graphical ''User Settings'' tool and the other is to use the adduser ‘’adduser’’ command-line tool. In this section we will look at both approaches.
To add a new user to your Ubuntu Linux system using the ''User settings'' tool select ''System'' desktop menu and choose ''Users and Groups'' from the ''Administration'' sub-menu. A dialog similar to the one shown below will appear:
[[Image:ubuntu_linux_user_settings.jpg|Ubuntu Linux User Settings Dialog]]
To add a new user , click on the ''Add User'' button. The ''New user account'' dialog will subsequently appear ready to be filled in with data relating to the new user, such as username, real name, password and contact information:
[[Image:ubuntu_linux_add_new_user.jpg]]
De-select any privileges you do not wish the new user to have. In particular you will want to ensure the user does not have ''Administration'' privilege unless the user is a trusted system administrator. The other privileges are usually considered to be safe for the typical user.
The final screen on the ''Add user dialog'' allows ''Advanced'' settings to be defined. These include such issues as the home directory of the user (traditionally /usr/''username''), tyhe type of shell that is presented as the command line in a terminal window (Bash is usually tyhe the defaultand there is no reason to change this unless you specifically need a different shell), the group to which the user belongs and the user ID. Use the drop down group menu to change the user's group membership to a different group:
[[Image:ubuntu_linux_user_advanced.jpg]]
Once the new user is configured, click on the ''OK'' button to add the new user. Once added the new user should appear in the list of users in the settings dialog and it should be possible to login in using the username and password specified.
As mentioned above it is also possible to add new users from the command-line. To do so startt up , start a terminal widnow window session and at the command prompt enter a command similar to:
<pre>
</pre>
The above command will prompt for a passowrd password for the account and optional contact information. Once the information has been gathered ''adduser'' creates the new account and the /home/john home directory. ''adduser'' provides a number of different options which can be learned from the man page:
<pre>
== Editing the Properties of a User ==
The properties of a user may be changed using the same ''User settings'' dialog used to add a user as outlined above. Select the ''System'' desktop menu and choose ''Users and Groups'' from the the ''Administration'' sub-menu to launch the ''User settings'' dialog. To make changes to the user properties select the user from the list and click on ''Properties''. Work the various screens in the ''Account Properties'' for the selected user and click on the ''OK'' button to apply the changes
== Deleting a User from an Ubuntu Linux System ==
An existing user may be deleted using the same User settings dialog used to add a user as outlined above. Select the System desktop menu and choose Users and Groups from the the Administration sub-menu to launch the User settings dialog.
Select the user to be deleted and click on ''Delete''. A confirmation dialog will appear. If you wish to proceed click on ''Delete''.
</pre>
The files in the user's home directory can also be backed up to another location before the directory is deleted using --backup-to commandline command-line option together with the path to the backup directory:
<pre>
== Adding a New Group to an Ubuntu Linux System ==
All users are members of one or more groups. As an administrator it makes sense to organise organize users into logical groups. For example all sales people might belong to a ''sales'' group, whilst accoutning accounting staff might belong to the ''accounts'' group and so on. New groups are added either using the ''Users settings'' graphical tool, or by using the ''addgroup'' command-line tool. In this section we will look at both methods.
To access the ''User settings'' dialog select the desktop ''System'' menu and choose ''Users and Groups'' from the ''Administration'' sub-menu. To administer the group settings click on the ''Manage Groups'' button. The ''Group settings'' dialog will appear, listing all the groups available on the system:
[[Image:ubuntu_linux_group_settings.jpg]]
To add a new group click on the ''Add Group'' and enter the name of the group youi you wish to add. Add the users that should belong to this group by checking the box next to each user name in the list. For example the following screenshot shows user John Smith being added to the new accounts group:
[[image:ubuntu_linux_add_group.jpg]]
</pre>
To remove a user from membership fof of a group use the following command syntax:
<pre>
sudo deluser john accounts
</pre>
