How to view and modify file read/write permissions in Linux

Statement for viewing file permissions:

Enter at the terminal:

Ls-l xxx. xxx (xxx. xxx is the file name)

Then similar information will appear, mainly including:
-Rw-r --

A total of 10 digits

The first one indicates the type.

The three rw in the middle represents the owner (user)

Then the three rw-represent the group)

The last three r groups represent other people (other)

Then I will explain the nine digits below:

R indicates that the file can be read)

W indicates that the file can be written)

X indicates that the file can be executed (if it is a program)

-The permission has not been granted.

Now let's talk about modifying file permissions.

Enter at the terminal:

Chmod o + w xxx. xxx

Grant other users the permission to write the file xxx. xxx.

Chmod go-rw xxx. xxx

Deletes the read and write permissions of group groups and other persons in xxx. xxx.

Where:

U stands for the owner (user)

G indicates the group in which the owner is located)

O stands for others, but not u and g (other)

A Represents all people, including u, g, and o

R indicates that the file can be read)

W indicates that the file can be written)

X indicates that the file can be executed (if it is a program)

Rwx can also be replaced by numbers.

R ------------ 4

W ----------- 2

X ------------ 1

------------- 0

Action:

+ Indicates adding permissions.

-Indicates the permission to be deleted.

= Indicates that it is the only permission

After everyone understands the above, we can easily understand the following common permissions:

-Rw ------- (600) only the owner has the read and write permissions.

-Rw-r -- (644) only the owner has the read and write permissions. The Group and others have only the read permissions.

-Rwx ------ (700) only the owner has the read, write, and execute permissions.

-Rwxr-xr-x (755) only the owner has the read, write, and execute permissions. The Group and others have only the read and execute permissions.

-Rwx -- x (711) only the owner has the read, write, and execute permissions. The Group and others have only the execution permissions.

-Rw-(666) everyone has the read and write permissions.

-Rwxrwxrwx (777) everyone has the permission to read and write and execute