File mode syntax
File modes are described by a nine characters string that follows the same scheme as the 
ls shell command:
| Position | Character | Meaning | 
|---|
| 1 | - | The file owner cannot read it. | 
|  | r | The file owner can read it. | 
| 2 | - | The file owner cannot write it. | 
|  | w | The file owner can write it. | 
| 3 | - | The file owner cannot execute it. | 
|  | x | The file owner can execute it. | 
|  | S | The file owner cannot execute it and the 'setuid' bit is set. | 
|  | s | The file owner can execute it and the 'setuid' bit is set. | 
| 4 | - | The file group cannot read it. | 
|  | r | The file group can read it. | 
| 5 | - | The file group cannot write it. | 
|  | w | The file group can write it. | 
| 6 | - | The file group cannot execute it. | 
|  | x | The file group can execute it. | 
|  | S | The file group cannot execute it and the 'setgid' bit is set. | 
|  | s | The file group can execute it and the 'setgid' bit is set. | 
| 7 | - | Other users cannot read the file. | 
|  | r | Other users can read the file. | 
| 8 | - | Other users cannot write the file. | 
|  | w | Other users can write the file. | 
| 9 | - | Other users cannot execute the file. | 
|  | x | Other users can execute the file. | 
|  | T | Other users cannot execute the file and the 'sticky' bit is set. | 
|  | t | Other users can execute the file and the 'sticky' bit is set. | 
See also