Chmod Master

755

-rwxr-xr-x

chmod 755 filename

Owner

Read

Write

Exec

Group

Read

Write

Exec

Public

Read

Write

Exec

How it works

4 = Read (r) Can view file content

2 = Write (w) Can edit/delete content

1 = Execute (x) Can run as program

0 = None (-) No access

The total number is the sum of permissions.
Example (7): 4 (Read) + 2 (Write) + 1 (Exec) = 7