Information about /etc/passwd file in linux/unix

The /etc/passwd file contains the list of all the users in Linux/Unix. It also contains some information related to the user. 

For example, the uid (user id) and gid (group id) of the user, home directory of the user, comment and login shell of the user.

The /etc/passwd file contains the information as shown below

 

This file contains 7 columns separated by colon (:)

1^st column: Contains the list of the user.

2^nd column: Contains x which means that password is stored in encrypted format in /etc/shadow file.

3^rd column: Contains the user id

4^th column: Contains the group id

5^th column: It contains the information related to the user

6^th column: It contains the home directory of the user

7^th column: The last column contains the login shell of the user.

Note:  

root user having 0 uid and gid. 1-499 uid is reserved for system user and 500 and more contains the uid or gid for normal users. 

usermod command is used to modify the fields in /etc/passwd file.