classnotes:rh124:permissions
File Permissions
There are 6 permissions in Linux
These are the standard ones Read write execute
| File Type | Owning User | Owning group | Other |
|---|---|---|---|
| d (directory) | rwx | r-x | — |
There are 3 special permissions
| Permission | effect on directory | effect on file |
|---|---|---|
| u+s (suid) | no effect | File executes as the user that owns the file, not as the user that ran the file |
| g+s (sgid) | Files that are created in the directory have a group owner to match the group owner of the directory | File executes as the group that owns the file. |
| o+t (sticky) | Users with write access to the directory can remove only files that they own; they cannot remove or force saves to files that other users own | no effect |
Sticky bit
- This applies only to directories
- Only the owning user can delete a file from a directory
- Applied with chmod o+t or chmod 1NNN
- Identified by a t in permissions for others
Permission will appear as a T if the execute permissions is not set for other. If this permission is set it will appear as lower case
SetGid bit
- Set on files and directories
- The owning group of a newly created file is derived from the directory that the file is created (for directory)
- THe executables run with the permissions of the owning group of the executablers (for files)
- To set use chmod g+s /dir or chmod 2NNN /dir or for files chmod g+s /file or chmod 2NNN /file
- Identifed by an s in permissions for the owning group
SetUID bit
- this is for files only
- executables run with permissions of the owning user of the executable
- to set use chmod u+s /file or chmod 4NNN /file
- identified by an s in the owning user
classnotes/rh124/permissions.txt · Last modified: by 127.0.0.1