How to view and modify file read and Write permissions under Linux system _unix Linux

Statement to view file permissions:
In the terminal input:
Ls-l xxx.xxx (xxx.xxx is file name)
Then there will be similar messages, mostly these:
-rw-rw-r--
A total of 10 digits
Which: the front one-represents the type
The middle one of the three rw-represents the owner (user)
Then the three rw-represent groups (group)
The last three r--represent other people (other)
And then I'll explain the 9 digits in the back:
R indicates that the file can be read (read)
W indicates that the file can be written (write)
x indicates that the file can be executed (if it is a program)
-Indicates that the appropriate permissions have not been granted
Now it's time to talk about modifying file permissions.
In the terminal input:
chmod o+w xxx.xxx
To give other people permission to write xxx.xxx this file
chmod GO-RW xxx.xxx
Indicates deletion of Read and write permissions for groups and other people in xxx.xxx
which
U on behalf of owner (user)
G represents the group in which the owner is located
O on behalf of others, but not u and g (Other)
A represents all the people, including U,g and O.
R indicates that the file can be read (read)
W indicates that the file can be written (write)
x indicates that the file can be executed (if it is a program)
Where: Rwx can also use numbers to replace

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

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

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

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

Let's go:

+ Indicates adding permissions

-Indicates delete permission

= means to make it a unique permission

When everyone is aware of the above, then some of our common permissions are easy to understand:

-RW-------(600) Only the owner has read and write permission

-rw-r--r--(644) Only the owner has read and write permission, the group and others only Read permission

-RWX------(700) Only the owner has access to read, write, execute

-rwxr-xr-x (755) Only the owner has the right to read, write, execute, group and others only read and execute

-rwx--x--x (711) Only the owner has permission to read, write, execute, group and others only execute

-rw-rw-rw-(666) Everyone has access to read and write

-RWXRWXRWX (777) Everyone has access to read and write and execute

This article comes from [BA degree space], the original link: http://www.8-du.net/Article/2008/0514/article_40239.html