Users and Groups
This help page is incomplete
Introduction
This module allows you to create, edit and delete Unix users and groups.
Typically, there is one Unix user account for each person who wants to
login to your system. In addition, various system programs will have
their own accounts, such as uucp or www. Every user
belongs to one or more groups, one of which is the primary group for
the user.
The main Users and Groups page shows all the local users and
groups on your system. NIS and NIS+ users and groups will not be shown
in the list, because they are not stored locally and cannot be edited.
However, groups can contain NIS users and users can have an NIS group
as their primary group.
If your machine is an NIS or NIS+ server and the table sources
are not /etc/passwd and /etc/group, you can change the
module configuration to edit the
appropriate files. The Command to run after change parameter can
be set to something like cd /var/yp ; make to update NIS maps
after every change to the password and group files.
Editing an Existing User
To edit a user, just click on the user's name from the list on the
main page. This will display a form in which you can edit the following
user details :
- Username
The name that the user uses to login to the system. Each user
must have a unique login name.
- Real name
The user's real name. This is stored in the comment field in
the password file.
- Encrypted password and Plain text password
The Unix password file stores passwords in one-way encrypted
form only. This means that the form cannot display the user's
plain-text password, only the encrypted form. To set a new
password for a user you can either enter the password into
the Plain text password field, or copy and paste an
encrypted string into the Encrypted password field.
- Password type
If you choose No password here, then no password is
needed to login to the account. If you choose Locked,
then no login is allowed. Only if Normal password is
chosen will the passwords described above be used.
- Unix UID
The UID is the number that the system really uses for
controlling access to files. Every user should have a unique
UID. If you change the Unix UID, then the Change UID
option at the bottom of the page determines what happens to
files owned by that user.
- Home directory
Every user should have a home directory to store personal files.
Typically, user home directories are all located under one
parent directory, such as /home.
- Shell program
When a user logs into the system, their shell program is run to
process whatever commands the user types. If a user has a shell
like /bin/false, then they will not be able to login.
This is useful for users who should only have FTP or email
access.
- Primary group
A user's primary group is the group which will usually be
assigned to any new files the user creates. If you change the
primary group, the Change GID option at the bottom
of the page controls what happens to files owned by that user
and group.
- Other groups
This is a list of all the other groups a user belongs to. Only
local groups will be shown, not NIS or NIS+ groups.
Some other user properties are only available if your system has a
shadow password file and the module configuration knows about it. They
are :
Creating a New User
To create a new user, click on the Create New User link below
the list of existing users on the main page. This will display the same
form as is used for editing a user, but with almost all the fields empty.
The only field that will be automatically filled in for you is the UID,
which Webmin will compute by picking a free UID at the end of a sequence
of existing UIDs.
When a new user is created, the user's home directory can be created as
well. To have webmin create and set the permissions on the directory you
specify, choose Create home directory at the bottom of the page.
You should do this for all normal users you add.
The Files to copy option in the module preferences can be used
to copy various files (such as .cshrc or .profile) into
the home directory of a newly created user. You should change this
parameter to a space-separated list of files to copy.
Deleting a User
To delete an existing user, click on the Delete button in the
user details form. This will take you to a page asking if you want to
delete the user's home directory as well. Be very careful when choosing
to do this, as some system users have the root directory as their
home directory.
In general, you should never change the UID, username or shell of system
users such as root, bin or nobody. Doing so
could make your system unusable or unbootable. Do not try to delete any
of these users either, especially root.
Editing an Existing Group
To edit a group, click on the group name from the list of groups on the
main page. This will bring you to a form in which you can edit the
following group properties :
- Group name
The unique name for this group.
- Group GID
Like this UID for a Unix user, this is a number that the system
uses to identify the group. Each group should have a unique
GID.
- Members
The list of all users in this group. This can include NIS or
NIS+ users as well, if they are in use on your system.
- Password
Not used?
Creating a New Group
To create a new group, click on the Create new group link
beneath the list of existing groups. This links to the same form as is
used for editing an existing group, but with all the fields blank except
for the GID. This is automatically filled by finding a free GID for the
new group.
Deleting a Group
To delete an existing group, click on the Delete Group button
on the group details page. This will immediately delete the group without
asking. No files or directories will be deleted though.
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