Why is there more than one Library folder?

You might have noticed that there is more than one Library folder on your hard disk. The Library folder in your home folder contains settings, preferences, and other resources that apply only to your account. There is a similar Library folder for every user on your Mac. There is also a Library folder at the root level of your hard disk. This Library folder contains resources that are used by every user on your Mac.

User Passwords

In Mac OS X every user has a password to log into their accounts. Administrator users will also use their password to install new applications and change some system settings. If a user forgets their password, an administrator can reset other users passwords. If you’re the only administrator and forget your password you can reset your password using the Mac OS X installation CD.

Restrict access to files and folders using file permissions

Mac OS X uses Unix file permissions to determine who can access a file or folder, and what they can do with it. You can view the permissions of a file or folder by selecting it in the Finder, going to the File menu and choosing View Info. In the window that appears click the disclosure triangle next to Ownership and Permissions to view what you can do with that file. To view more details of the file’s permissions click the disclosure triangle next to Details. If you want to change the permissions for a file, simply click the lock icon and then type in an administrator password.

Log in and out of your account when using multiple users on your Mac

Having your Mac log into your account automatically is convenient when you’re the only user on your Mac, but when you share a Mac with others it can leave you feeling a bit insecure. If you share your Mac with others you might want to set your Mac to go to a login window when starting up. In the Security preference pane, select “Disable automatic login” and the next time you restart your computer a password will be required to access any account on your Mac.

Use fast user switching to access multiple accounts without logging out

If you share your Mac with other users you can easily switch between users without logging out using fast user switching. When you use fast user switching to move between users on your Mac the first user doesn’t have to log out, and all of the applications they are using remain open so they can pick up where they left off when they switch back to their account. You enable fast user switching in Accounts under System Preferences.

Use the Public and Shared folders to share files with other users

Mac OS X has two locations that you can use to share your files with other users. The Shared folder, located in the Users folder, can be accessed by any user of a particular computer, which makes it a great location for shared files. In every user’s home folder there is a Public folder. This folder can be accessed by any user of the computer or on the network.