Next: 3.10 Managing file links Up: 3.9 File Permissions Previous: 3.9.3 Dependencies

## 3.9.4 Changing permissions

The command `chmod` is used to set the permissions on a file. Only the owner of a file may change the permissions on that file. The syntax of `chmod` is:

`chmod {a,u,g,o}{+,-}{r,w,x}`

Briefly, you supply one or more of all, user, group, or other. Then you specify whether you are adding rights (`+`) or taking them away (`-`). Finally, you specify one or more of read, write, and execute. Some examples of legal commands are:

`chmod a+r stuff`
  Gives all users read access to the file.
`chmod +r stuff`
  Same as above---if none of `a`, `u`, `g`, or `o` is specified, `a` is assumed.
`chmod og-x stuff`
  Remove execute permission from users other than the owner.
`chmod u+rwx stuff`
  Allow the owner of the file to read, write, and execute the file.
`chmod o-rwx stuff`
  Remove read, write, and execute permission from users other than the owner and users in the file's group.

Next: 3.10 Managing file links Up: 3.9 File Permissions Previous: 3.9.3 Dependencies