====== [DOC] Linux special permissions ======
====== Meanings ======
^ Special Permissions ^ On a File ^ On a Directory ^
^ SUID or Set User ID | A program is executed with the file owner's permissions (rather than with the permissions of the user who executes it). | Files created in the directory inherit its UID. |
^ SGID or Set Group ID | he effective group of an executing program is the file owner group. | Files created in the directory inherit its GID. |
^ Sticky (bit) | A program sticks in memory after execution. | Any user can create files, but only the owner of a file can delete it. |
====== Reading ======
^ Permissions ^ Meaning ^
| --S------
| SUID is set, but user (owner) execute is not set. |
| --s------
| SUID and user execute are both set. |
| -----S---
| SGID is set, but group execute is not set. |
| -----s---
| SGID and group execute are both set. |
| --------T
| Sticky bit is set, bot other execute is not set. |
| --------t
| Sticky bit and other execute are both set. |
====== Applying ======
^ Permissions ^ Apply ^ Ressult ^
| --S------
| chmod 4000 file
| ---S------ 1 root root 0 May 15 11:14 file
|
| --s------
| chmod 4100 file
|---s------ 1 root root 0 May 15 11:14 file
|
| -----S---
| chmod 2000 file
|------S--- 1 root root 0 May 15 11:14 file
|
| -----s---
| chmod 2010 file
| ------s--- 1 root root 0 May 15 11:14 file
|
| --------T
| chmod 1000 file
|---------T 1 root root 0 May 15 11:14 file
|
| --------t
| chmod 1001 file
|---------t 1 root root 0 May 15 11:14 file
|