"Linux learning is not difficult" user management (2):/etc/passwd File Detailed Introduction

9.2 "Linux learning is not difficult" User Management ( 2 ): /etc/passwd File Details

/etc/passwdfile isLinuxThe system identifies an important file for the user,Linuxall users in the system are logged in the file. Assume that the user has an accountZhangsanwhen you log in to the system, the system first checks/etc/passwddocument to see if there isZhangsanThis account and then determine the userZhangsanof theUID, throughUIDto confirm the identity of the user and read if there is/etc/shadowthe corresponding password in the file. If the password is verified correctly, log in to the system and read the user's configuration file.

any user can read /etc/passwd the contents of the file, /etc/passwd file, each line represents a user account information, one row has 7 Dan, each of the ":" delimited, below is /etc/passwd part of the file.

Root:x:0:0:root:/root:/bin/bash

Bin:x:1:1:bin:/bin:/sbin/nologin

Daemon:x:2:2:daemon:/sbin:/sbin/nologin

........................ Omitted

Sshd:x:74:74:privilege-separated Ssh:/var/empty/sshd:/sbin/nologin

Oprofile:x:16:16:special user account to being used by Oprofile:/var/lib/oprofile:/sbin/nologin

Tcpdump:x:72:72::/:/sbin/nologin

zhangsan:x:1000:1000: Zhang San:/home/zhangsan:/bin/bash

shown in the table is /etc/passwd the meaning of the fields in the file.

dan	meaning
user name	also known as the login name, the user name should be unique within the system. In this example, the zhangsan
password	store encrypted user's password and see a x In fact the password has been mapped to /etc/shadow
user identification Number ( UID )	identify users with an integer within the systemID, each user'sUIDAre the only,RootUser'sUIDis a0, the average user'sUIDDefault from +start, the user in this exampleZhangsanof theUIDis a +
Group identification number ( )	Identify the primary group to which the user belongs by using an integer within the system id gid
username full name	user name description, can not be set. In this example, zhangsan The user's full name is Zhang San
main directory	First entry directory after user login system, zhangsan The user's home directory is /home/zhangsan
login Shell	user-Used Shell type, Linux The system uses the default Shell is a /bin/bash

This article extracts from "Linux Learning is not difficult" textbook, which is one of the most practical, theoretical and practical Linux Introductory materials.

"Linux learning is not difficult" user management (2):/etc/passwd File Detailed Introduction