# chmod +t: The Sticky Bit Explained

> Sets the sticky bit: only a file's owner can delete or rename it in a shared directory.

In a directory everyone can write to, anyone can normally delete anyone else's files. The sticky bit stops that: a file can only be deleted or renamed by its owner, the directory's owner, or root.

It's why `/tmp` is mode 1777 — writable by all, but nobody can clean out your files.

## What it changes

`drwxrwxrwx` → `drwxrwxrwt` (the t replaces the others' x)

## Examples

```
chmod +t /srv/dropbox
```

add the sticky bit to a shared directory

```
chmod 1777 /srv/dropbox
```

the full /tmp-style mode in one go

```
ls -ld /tmp
```

see it in action: drwxrwxrwt

```
chmod -t /srv/dropbox
```

remove it

## Good to know

- A lowercase `t` means sticky plus execute for others; a capital `T` means sticky without it, so others can't enter the directory at all.
- Linux ignores the sticky bit on files. It only means something on directories.
- Sticky stops deletion and renaming, not writing: if a file itself is world-writable, others can still change its contents.

## FAQ

### What does chmod +t do?

It sets the sticky bit. On a directory, users can only delete or rename files they own, even if the directory is writable by everyone.

### Why is /tmp drwxrwxrwt?

/tmp has mode 1777: every user can create files there, and the sticky bit (the final t) stops users from deleting each other's files.

### What is the difference between t and T in ls -l?

Both mean the sticky bit is set. Lowercase `t` means others also have execute permission; capital `T` means they don't.

## Related

- [chmod 1777](https://www.devkult.com/chmod/1777.md)
- [chmod 777](https://www.devkult.com/chmod/777.md)
- [chmod g+s](https://www.devkult.com/chmod/g-plus-s.md)
- [chmod u+s](https://www.devkult.com/chmod/u-plus-s.md)

Open the interactive page: https://www.devkult.com/chmod/plus-t