1. When Linux file permissions are represented by numbers, it’s called numeric mode. In numeric mode, a three-digit value represents specific file permissions (for example, 744.) These are called octal values. The first digit is for owner permissions, the second digit is for group permissions, and the third is for other users. Each permission has a numeric value assigned to it:

r (read): 4

w (write): 2

x (execute): 1

2. In the permission value 744, the first digit corresponds to the user, the second digit to the group, and the third digit to others. By adding up the value of each user classification, you can find the file permissions.

3. For example, a file might have read, write, and execute permissions for its owner, and only read permission for all other users. That looks like this:

Owner: rwx = 4+2+1 = 7

Group: r– = 4+0+0 = 4

Others: r– = 4+0+0 = 4

The results produce the three-digit value 744.

4.All files should have permissions set to 644.

5.All folders should have permissions set to 755.