Chmod 111 Explained
Chmod 111: execute-only for everyone. Nobody can read or write. Used for compiled binaries where source protection is needed.
Permission
111
--x--x--x
chmod 111 filename
Permission Breakdown
| Role | Read (4) | Write (2) | Execute (1) | Octal | Meaning |
|---|---|---|---|---|---|
| Owner | - | - | x | 1 | execute |
| Group | - | - | x | 1 | execute |
| Others | - | - | x | 1 | execute |
Visual Permission Grid
Detailed Explanation
The permission 111 grants only execute access to everyone, denying read and write permissions.
Octal breakdown:
- 1 (Owner): execute (1) only
- 1 (Group): execute (1) only
- 1 (Others): execute (1) only
In symbolic notation this is --x--x--x. Everyone can execute the file, but nobody can read or write to it. For directories, everyone can traverse into the directory but cannot list its contents or create files.
For compiled binaries, this works as expected: the kernel can load and execute the binary even though the user cannot read it with cat or copy it. For scripts (shell, Python, etc.), this does not work well because the interpreter needs to read the script file. For directories, execute-only means users can access files by exact path but cannot list what files exist (similar to 711 but without any read access for the owner).
Use Case
Used for compiled proprietary binaries where users should be able to execute the program but not read, copy, or modify the binary. Also used for traversal-only directories.