*NIX permissions are represented as one or more of the following:
| Permission | Symbolic | Numeric |
|---|---|---|
| Read | r | 4 |
| Write | w | 2 |
| Execute | x | 1 |
| SUID | s/S | 4 |
| SGID | s/S | 2 |
| Sticky Bit | t | 1 |
The SUID/SGID bits are applied to the user or group (respectively) when set symbolically; the sticky bit is applied to the “other” permission set. When set numerically, all three of these values are applied to the “prefix” digit.
Symbolically, the SUID/SGID bits can be represented as either s or S. The different is whether the user/group also has execute permissions (s), or lacks these permissions (S).