Controlling File Permissions

In addition to letting you decide who can log in to your computer, Mac OS X enables you to control who can interact with your files. If you create a file while you're logged in to your account, you own that file. Without your password, other users can be prevented from accessing your folders and files in any way; they can neither read nor alter your files and folders. For example, the folders in the home folder created for each user have some of these restrictions set by default.

Changing privileges in a file or folder is done though the Info panel of the Finder. These are the steps to use this panel:

1. Highlight the icon of the file or folder whose access you want to change. Users who are administrators can change the permissions on almost any file, but those who are normal users can change the permissions only on files they themselves own.

2. To open the Info panel, choose Get Info from the File menu. Alternately, you can use the key command Command-I.

3. Open the Ownership & Permissions section of the panel. If the lock button shows a closed lock, click it to unlock the settings.

4. Access can now be set so that different users have different privileges. The main options for levels of access are Read & Write, Read Only, and None. For folders, there is also the Write Only option, which enables a drop-box feature so that users can copy files into the folder, but only the owner can view it.

5. When you've set the permissions you need, close the panel.

When changing access options for a folder, you also have to Apply to Enclosed Items button to apply the access rights you've selected to all files and folders within the original folder. Remember, just because a folder doesn't have read permissions doesn't mean that the files inside it can't be read or modified.