Linux (11) Rights Management

11.1 rwx Permissions Detailed 11.1.1 rwx effect to file

(1) "R" stands for readable (read): Can read, view.

(2) "W" for Writable (write): Can be modified, but does not mean that the file can be deleted, deleting a file if you have write permission to the directory where the file is located in order to delete the file.

(3) "X" means executable (execute): can be executed.

11.1.2 rwx effects to the directory

(1) "R" stands for readable (read): Can read, view.

(2) "W" stands for Writable (write): You can modify, create, delete, and rename directories within the directory.

(3) "X" means executable (execute): You can enter the directory.

11.2 Practical Cases

-rw-r--r--. 1 root root 26788 4月  14 16:53 java后端生活.jpg

? The preceding 10 characters -rw-r--r-- determine what different users can do with the file:

The first character represents a file type: File (-), directory (d), link (l);

The rest of the characters are each 3 groups (RWX):

First set of rw-: The permissions of the file owner are read and write, but cannot be executed;

Second set of r--: The permissions of the user in the same group as the file owner are read-only and cannot be written and executed;

Third group r--: the permissions of other users who are not in the same group as the file owner are read-only and cannot be written and executed;

The available numbers are expressed as: r=4,w=2,x=1; so rwx=4+2+1=7

1: File is a hard connection number, directory is a subtree

Root: User

Root: Group

26788: File Size (bytes), if folder is displayed 4096 bytes

April 14 16:53: Last Modified Date

Java back-end life. jpg: File name

11.3 Modifying permissions 11.3.1 basic instructions

With the chmod directive, you can modify the permissions of a file or directory

11.3.2 First way: + 、-、 = Change permissions

U: Owner

G: Group

O: Others

A: Everyone (sum of u, G, O)

(1) chmod u=rwx,g=rx,o=x file directory name

(2) chmod o+w file directory name

(3) chmod a-x file directory name

11.3.3 Second way: Change permissions by number

Rule: r=4,w=2,x=1,r+w+x=7

chmod u=rwx,g=rx,o=x file directory name

Equivalent to chmod 751 file directory name

11.4 Modify File Owner 11.4.1 Basic Introduction

Chown Newowner file Changes the owner

Chown Newowner:newgroup file changes the owner and group of files

-R If it is a directory, make all sub-files and directories under it recursively take effect

11.5 Modifying the group of files

CHGRP newgroup file changes the group in which the files are located

Linux (11) Rights Management