Users and Groups

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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 :

  • foo
    foo.


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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