Chmod 651 Explained
Chmod 651: owner rw, group rx, others execute-only. A fine-grained permission separating access levels across roles.
Permission
651
rw-r-x--x
chmod 651 filename
Permission Breakdown
| Role | Read (4) | Write (2) | Execute (1) | Octal | Meaning |
|---|---|---|---|---|---|
| Owner | r | w | - | 6 | read, write |
| Group | r | - | x | 5 | read, execute |
| Others | - | - | x | 1 | execute |
Visual Permission Grid
Detailed Explanation
The permission 651 gives the owner read-write, group read-execute, and others execute-only access.
Octal breakdown:
- 6 (Owner): read (4) + write (2) = read and write
- 5 (Group): read (4) + execute (1) = read and execute
- 1 (Others): execute (1) only
In symbolic notation this is rw-r-x--x. The owner can read and modify the file. Group members can read and execute it. Others can only execute it but cannot read or modify it.
This permission creates a three-tier access model: the owner maintains the file, trusted group members can inspect and run it, and everyone else can only run it without seeing the source. This is useful for compiled programs or proprietary tools distributed on a shared system.
Use Case
Used for proprietary utilities on multi-user systems where group members need read access for debugging, but general users should only be able to execute the program.