chmod 640

What does chmod 640 mean?

Chmod (change mode) is a UNIX/Linux command that you can use to change permissions on a file. Here we will explain how the chmod 640 UNIX/Linux command changes your file permissions. We start by color-coding the three digits in 640, like this, so it is easy to follow along:

640

The three digits refer to three different permissions:

6: Owner Permissions
4: Group Permissions
0: Everyone Permissions

Furthermore, chmod digits give the following kind of permissions:

1 = Execute
2 = Write
3 = Write & Execute
4 = Read
5 = Read & Execute
6 = Read & Write
7 = Read, Write & Execute

Now, when we put it all together, we can see what the chmod 640 command means and what it will do to your file permissions:

6: Owner can read and write
4: Group can read
0: Everyone can do nothing

chmod 637
Here is the next chmod command on our list that we have explained for our fellow UNIX/Linux fans.

File Permissions Calculator
You may also be interested in our File Permissions Calculator for more information.