理解 /etc/passwd

转载: http://www.cyberciti.biz/faq/understanding-etcpasswd-file-format/

 

The /etc/passwd contains one entry per line for each user (or user account) of the system. All fields are separated by a colon (:) symbol. Total seven fields as follows.

 

 

Username: It is used when user logs in. It should be between 1 and 32 characters in length.

Password: An x character indicates that encrypted password is stored in /etc/shadow file.

User ID (UID): Each user must be assigned a user ID (UID). UID 0 (zero) is reserved for root and UIDs 1-99 are reserved for other predefined accounts. Further UID 100-999 are reserved by system for administrative and system accounts/groups.

Group ID (GID): The primary group ID (stored in /etc/group file)

User ID Info: The comment field. It allow you to add extra information about the users such as user's full name, phone number etc. This field use by finger command.

Home directory: The absolute path to the directory the user will be in when they log in. If this directory does not exists then users directory becomes /

Command/shell: The absolute path of a command or shell (/bin/bash). Typically, this is a shell. Please note that it does not have to be a shell.