Linux Getting Started Basics (vii) Linux permissions mechanism

Permissions

Permissions are the mechanisms used by the operating system to restrict access to resources, and permissions are generally divided into read, write, and execute. Each file in the system has specific permissions, the user and the group it belongs to, by which users are restricted and which groups are able to operate on specific files.

Each process is run as a user, so the process has the same permissions as the user, and the greater the user's permissions, the more permissions the process has.

Permissions for files

The directory must have X permission or it cannot view its contents. X is also called browsing permission

UGO

Linux permissions are controlled based on the UGO model:

U represents user,g on behalf of Group,o

Permissions for each file are set based on Ugo

Permission three group (RWX), corresponding Ugo respectively set

Each file has a user and a owning group, corresponding to UG, does not belong to the user of the file or the group to use O permission

Command ls-l can view file information in the current directory

Drwxrwxr-x 2 shuangde shuangde 4096 August 00:33 HDU

-rw-rw-r--1 Shuangde shuangde 26 August 22:50 Input.txt

Drwxrwxr-x

D: File type, D is directory,-represents a normal file

Rwx:u Permissions

Rwx:g Permissions

R-x: Other permission,-the delegate does not have this permission