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Fanny G
1st October 2015, 03:10 AM
User Management
Introduction:
It is very important that when you have a Linux system, which is multiuser, good management of users take as this will depend largely on system security. That is why you must know the needs to manage appropriately.

While working on the Linux system, each user must be identified and in this way is as privileges are distributed, depending on the type of user and thus also has a greater care than other areas of the system are not affected in the which the user would normally not have access.

Developing:
Gonzalez Duran as we mentioned in his article "User management" becomes very routine task to add, modify, delete, or any other activity to manage users on the Linux system, which is very important to know the basic principles and everything needed to manage users of the system properly.

There are three types of users which are:
Root: This user, who is also known as root or administrator owns the system so it is the only one with privileges on the system cough, also it has a UID of 0.

Regular users: These users can log on to the system plus they have a working directory and privileges are only these. It is recommended to always work with these users and their UID typically they are greater than 500.

Associated services users: These users, also called system accounts can not log on to the system but can access their services. Also they do not have passwords and usually have a UID of 0-100.

Some basics admisnistrar the time of users on a Linux system are:

Login: This is the nickname with which the user is identified, it is unique
Password: Password to login to the system
Full Name: Full name of the user or the function performed
Group: Used when the account is associated with a group, if it is not associated with any user name is displayed.
Home Directory: This is where you log structure under / home
Shell Connection: shells that are used are specified by users.

In addition to managing users have some files which are:

/ Etc / passwd
In this file they are defined all user accounts.
Its structure is as follows:
Login: x: UID: GID: Description: Directory: Shell

As for example:
sergio: x: 501: 500: Sergio Gonzalez: / home / sergio: / bin / bash

User information is divided into seven fields identified by the colon ":"
Field Description
1 LOGIN User
2 A x is the encrypted password for the user is displayed
3 Number of user identification, is unique
4 Number of group identification
5 full User Name
6 Working Directory User
7 Shell used by the user


/ Etc / shadow
In this file the encrypted password is stored users and contains one line for each user. It can only be read by root.

Structure:
Nom: Pass changed: minlife: maxlife: warn: inactive: expired: unused

As for example:
sergio: rfgf886DG778sDFFDRRu78asd: 10568: 0: -1: 9: -1: -1 ::

User information is divided into 9 fields which are identified by the colon ":"
Field Description
1 LOGIN User
2 encrypted user password, an * appears nologin account
3 How many days have passed since the 01/01/1970 until the date on which the password was last changed
4 How many days must pass before you can change your password again
5 Number of days to have to change the password. If -1 means never
6 Number of days before the password expires that the user will be warned
7 Number of days to inactivate after the password expires
8 Date of expiry account
9 reserved Campo


/ Etc / group
In this file the relationship between groups and users of the system is saved.

Structure:
root: x: 0: root

As for example:
Cristina: x: 503: sales, Sergio

User information is divided into 4 fields identified by the colon ":"
Field Description
1 LOGIN User
Password Group 2
3 It is the GID, group ID
4 is optional, list of groups to which the user belongs

Some user management commands that are used by root are:

Create new users useradd
Common or important options:
• -c add a comment to create the user
• -d working directory or home user
• -e expiration date of the account
• -g number of user's primary group (GID)
• -G other groups they may belong to the user, separated by commas.
• -r creates a system account or special
• -s shell of the user when entering the system.
• -u UID User

Modify a user usermod
Common or important options:
• -c add or modify the comment
• -d modifies the working directory or home user
• -e change or set the expiration date of the account
• -g changes the user group number (GID)
• -G sets other groups that the user belongs
• -l changes the login or username
• -s shell changes the user when entering the system.
• -u changes the UID of the user.

Userdel Delete a user
Change a user password passwd

Also in the article by Gonzalez Duran is a list of commands and files comprehensive user administration among which we can mention:

See useradd adduser
chage change or set control parameters dates
chpasswd update or set passwords in batch mode,
id Displays user identity (UID) and the groups to which belongs.
Manage passwords gpasswd groups
groupadd Adds groups to the system
Eliminates groupdel system groups.
groupmod modifies system groups.
groups Shows the groups to which the user belongs.
newusers update or create users in batch mode


Conclusion:
Upon manage users on an operating system, such as Linux, it is essential that privileges are assigned as in this way will prevent unwanted users do not enter or modify parts of the system are supposed to not change.

You also need all user management commands so that the root user can keep good control of them and improve system performance which after a time becomes so routine that will not be necessary to consult or investigate commands the function of each.

(translated by Google Translate - Bob) PLEASE MAKE ALL POSTS IN ENGLISH

lsatenstein
1st October 2015, 03:23 AM
I read the above, and Fanny G is really presenting an expository, rather than asking about solving a problem.

Hola Fanny G

Soy un canadiense que entiende algo de español. Le agradezco su presentación, y yo sugeriría que se pasa a través de Google traducir y publicar de nuevo a este foro. Incluso con la traducción de Google, se entenderá por el lector medio.

Está bien hecho

Español es como el francés. Y francesa es como español.
Sr. Leslie

giulix
1st October 2015, 07:57 AM
Must be the new version (http://forums.fedoraforum.org/showthread.php?t=303406) ;)

glennzo
1st October 2015, 08:44 AM
Fanny G, please read the posting rules.

11). Don't post in languages other than English.
Fedora and FedoraForum.org are both* located in the USA. While we have an international membership, we must insist that English is used in all posts as questions and solutions must be standardized and the staff must be able to understand them. Threads and posts in other languages will be closed with instructions to post again in English. Please don't worry or apologize about imperfect English. Forum members understand this issue well and will compensate for English language errors. *(Note: FedoraForum.org itself is not officially connected with or sponsored by FedoraProject or Red Hat, Inc.).