I had downloaded this interesting freeware program called Pacifist
a few days ago, but until this morning, I hadn't actually tried it. I wish I would have launched it sooner! [Update: It's now a $20 shareware item]
Pacifist is an attempt to provide a "Tome Viewer" application for OS X. Tome Viewer allowed you to browse OS 9 installation packages and extract only those bits that you wanted; Pacifist's goal is to offer the same features for OS X.
Why might this be useful? If you deleted Sherlock, for example, you would need to re-run the OS X installer, and it's doubtful that you would have a CD that matches the current 10.1.2 version. So if you follow Apple's advice, you'd have to reformat your drive, install 10.1 from CD, then upgrade to 10.1.2 just to get Sherlock back.
Using Pacifist, it's a much simpler process. Insert your 10.1 CD, launch Pacifist, and nagivate to System -> Installation -> Packages and then open Essentials.pkg
. Pacifist will display a list of everything installed from Essentials.pkg, one of which is Sherlock. Select "Extract To..." from the File menu, and you've now reinstalled Sherlock.
Of course, Pacifist can work on any .pkg file, not just the Mac OS packages. Well worth the download time, and I now consider Pacifist a key member of my troubleshooting team!