Access bits

`` SUUUGGGOOO


S is special.

Symbol | Meaning
---   | ---
`-` | file
`d` | directory
`l` | link

The others are one of `r`, `w`, `x`, or `-`.

U is for user who is the owner.

G is for user group.

O is for other users.


## Levels

Number | Octet
--- | ---
0 | `---`
1 | `--x`
2 | `-w-`
3 | `-wx`
4 | `r--`
5 | `r-x`
6 | `rw-`
7 | `rwx`


## Commands

```sh
$ chmod VALUE PATH

Modify

All

This will update for all users.

Add access for r, w, or x.

$ chmod +x

Remove.

$ chmod -x

Target

Restrict to owner, group, or other.

$ chmod u+x

Set number

Read, write, and execute permissions for everyone.

$ chmod 777

Read, write, and execute permissions for the user only.

$ chmod 700

Write and execute permission for the user, write for the group, and read, write, and execute for the users.

$ chmod 327

Set bits

$ chmod USERS=LEVEL
$ chmod USERS=LEVEL,USERS=LEVEL

e.g.

$ chmod ug=rw,o=r,a+X

Recursive

If you set permissions on a directory, it will not apply to files and directories inside it. Unless you use the recursive flag.

e.g.

$ chmod -R VALUE PATH

Using find.

$ find PATH -exec chmod VALUE {} +

This can be useful to filter to say just directories with find -type d.