Mac OS X Hints Page 2 of 2

Help Desk

Check It Out: Select Multiple Desktop or Screen-Saver Images in iPhoto

iPhoto lets you easily set your desktop to anything you’d like—just click on the desired desktop image and then click on the Desktop button. But do you know that there’s some simple magic hiding just below iPhoto’s interface?

Instead of selecting one picture, hold down Command (to choose noncontiguous images) or shift (for contiguous images) to select more than one. Now click on the Desktop button. Open the Desktop & Screen Saver preference pane, and you’ll find that your desktop is now set to rotate through the pictures in your iPhoto Selection. If you click on the Screen Saver tab, you’ll also find that your screen saver is set to use the same iPhoto selection.

You can update your selection of images in iPhoto at any time; when you click on the Desktop button, the newly chosen photos will replace the existing set.

Unix Tip of the Month: Disable Guest Access to Your Mac

In the pre-OS X days, an easily accessible option let you disable guest access to your computer with Personal File Sharing running. With the advent of OS X, however, that easy option vanished—anyone can connect to your machine and see what’s in your Public folder (even if it’s just your Drop Box, where someone can secretly add a file to your computer). If you’re extremely security conscious, you can disable guest access.

Open Terminal and type

cd /Library/Preferences

. You’ll be editing a system-level preferences file, so it’s a good idea to make a backup first by typing

sudo cp com.apple.AppleFileServer.plist com.apple.AppleFileServer.bak

Next, use a Unix text editor such as pico to edit the file. Open the file by typing

sudo pico com.apple.AppleFileServer.plist

and providing your password when asked. Press control-W to search, type

guest

, and press return. You should see these lines:

<key>guestAccess</key>

<true/>

Change

true

false

. Press control-O and then enter to save the file, and control-X to exit. To make your changes take effect, you need to restart Personal File Sharing. You could do this via the GUI, of course (in the Sharing preference pane), but since this is a Unix hint, here’s the command-line solution:

sudo killall -HUP AppleFileServer

Now when someone tries to connect to your computer, the Guest option won’t be available.

Selecting multiple pictures and clicking on iPhoto’s Desktop button is an easy way to create a varied collection of desktop images without creating a special album.

Disabling Personal File Sharing’s guest-access mode in Terminal will give visitors a grayed-out Guest button—letting them know that your Mac is reserved for registered users only.