====== [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|