Retrieve Keychain Passwords

With the ability to store and encrypt any password on Macintosh systems, the Keychain can be a mixed blessing. It's easy for users to save time and effort with a single sign-on system for email, website, and file sharing access. It's equally easy to lose track of passwords that, thanks to a secure and convenient alternative, people seldom type themselves. Most users know the pain of an important but forgotten password. Next time it happens, there's a painless way to save their day.

In the Utilities folder you'll find the often-overlooked Keychain Access. Open it, and scroll down the main window to find the password item you need. If a user has multiple keychains, you may have to search more than one, but you can skip those named "System" and "System Roots" in Leopard (as well as "X509Anchors" and "X509Certificate" in Tiger). Select "Get Info" from the file menu to see the entry details, then click on the "Show password" button and enter the owner's main keychain password.

If your users can't rescue an essential password from their memories, this approach can retrieve it from the OS X Keychain instead.

Recommended Reading: Giles Turnbull has an extensive overview of Keychain Access available at the extensive O'Reilly MacDevCenter.

Remote Control From Windows

It's ten o'clock at night when you get the call: The art department's having an issue on the XServe. On Mac OS X, you could use Apple Remote Desktop to access the machine, but Apple doesn't offer administration tools for Windows. How can you control a Mac remotely when you aren't using a Mac yourself?

The answer is VNC (Virtual Network Computing), an open source desktop sharing system built directly into Mac OS X (and at the center of Apple's new "Back To My Mac" and screen sharing features in Leopard). Once configured as a VNC server, any Macintosh system can be accessed from a Windows VNC client, allowing you to view and control the current user session.

Open System Preferences on your Macintosh and choose "Sharing" from the third row. In the Sharing pane, check "Remote Management" from the "Service" column, then click the "Computer Settings..." button (called "Apple Remote Desktop" and "Access Privileges" respectively in Tiger). When the settings dialog appears, check "VNC viewers may control screen with password", and choose a strong password to enable remote access. If the Mac you're trying to reach isn't on the same network as your client machine, you'll need to configure your router or firewall to forward port 5900 to it as well.

That's it. Now when you need to remotely control that Mac, you can point the VNC client of your choice at the machine's IP and log in with the password you just assigned. There's no further authentication process built in (and no data encryption being used), so you'll want at the very least log out of that machine when it's not in use to minimize security risks. You'll also need to set your VNC client to utilize full color (the highest possible color depth) to get around a bug in Apple's VNC Server.

This kind of screen sharing isn't an ideal long term management solution, but it allows the kind of emergency troubleshooting that can often save the day. The next day, you can look into buying a MacBook Pro.

Recommended Reading: If you aren't currently using VNC on Windows, you can check out RealVNC, UltraVNC, and TightVNC, all popular and free VNC clients. For those who can't decide, Wikipedia offers a fantastic feature comparison of remote desktop software which includes these options, Apple Remote Desktop, and others.

Resize Macintosh Partitions

In the past, changing the size of a Macintosh volume has been a significant undertaking, requiring third-party tools, offline reformatting, or both. This tended to complicate storage management, and made it difficult to handle unexpected demand.

Fortunately, all that changes in Leopard. In the newest version of OS X, you can grow or shrink any HFS+ partition, whether it's a local hard drive or a mounted network array. The resizing is done live, while the disk is online, and can even be performed on a mounted boot volume (though you'd want a good backup before trying it).

Open Disk Utility and select the storage device you're resizing in the left column, clicking the "Partition" button on the pane to the right. What you'll get is a graphical representation of the entire storage space, with the portion currently being used in purple and the available space left on that partition in white.

To grow a volume to fill the whole disk or array, grab the diagonal markings on the active partition and pull down until it reaches the size you need. To shrink a volume to repurpose unused space, simply drag upward on the same boundary. If you need to add or subtract empty partitions, you can do so with the "plus" and "minus" buttons. Once you've made your adjustments, just click "Apply" and your Macintosh partitions can finally be resized instantly.

Recommended Reading: Back when it was an undocumented feature available only on the command line, Kirk McElhearn wrote about how to resize partitions on the fly with OS X 10.4.6 (and a whole lot of luck) for MacWorld magazine.

Display Hidden Files In Finder

Hidden files in Mac OS X keep essential operating system data safe from casual tampering. The technique leaves the Finder uncluttered and easy to navigate, and diminishes the chance of accidental damage. But hidden files also the contain preferences for command line tools, serial numbers for commercial products, access controls for HTML directories, and the entire Unix subsystem that keeps your Macintoshes running. They're often useful for troubleshooting, and the ability to temporarily access them can be an invaluable tool for administrators.

Fortunately, there's a painless way to display these files when you're tracking down a problem on someone else's machine, and just as importantly a way to hide them again when you're done. Open the Terminal and type the following:

defaults write com.apple.finder AppleShowAllFiles -bool TRUE

Now hold down the option and command keys, and select the Finder icon in the dock. Choose "Relaunch" from the pop-up menu, and when your windows redraw they'll be full of your invisible files and folders, distinguished with lighter colored icons.

Keep in mind that working with hidden files can disable or even destroy your operating system. So when you're done, you'll want to put the system back the way you found it. To safely conceal your previously-hidden files, just run the above command again, replacing TRUE with FALSE and relaunching the Finder afterwards.

With this technique, you can harness the power of the command line while retaining the convenience of the graphical interface.

Recommended Reading: Ted Landau has a great article on the various kinds of "Invisible Files in Mac OS X" at MacFixit. Even more exhaustive is Gordon Davisson's wonderful chart of "Mac OS X Hidden Files & Directories", from Seattle's Westwind Computing.