# chmod 444 — What It Means & When to Use It

> Everyone can read; nobody can write or execute. Symbolic: `r--r--r--` · Safe when used as intended.

444 is read-only for everyone — the owner included. It guards against accidental edits and deletions by scripts and editors, while still letting anyone read the file.

It isn't a lock: the owner (and root) can always `chmod` it back.

## Permission by permission

| Who | Permissions |
|---|---|
| owner | read only |
| group | read only |
| others | read only |

Symbolic chmod argument: `u=r,g=r,o=r`

## Use it for

- Reference data and generated files that must not be edited by hand.
- Published files you want protected from accidental overwrite.

## Avoid it for

- Secrets — everyone can read them. Use `400`.
- Files a tool regenerates: it will fail with 'Permission denied'.

## FAQ

### Can the owner still modify a 444 file?

Not directly — writes fail. But the owner can chmod it back to 644 at any time, so treat 444 as a safety catch, not security.

## Related modes

- [chmod 400](https://www.devkult.com/chmod/400.md): Only the owner can read; nobody can write or execute
- [chmod 644](https://www.devkult.com/chmod/644.md): Owner can read and write; everyone else can read
- [chmod 600](https://www.devkult.com/chmod/600.md): Only the owner can read and write

Open the interactive page: https://www.devkult.com/chmod/444