You may have already seen hints on mdutil (used to control Spotlight) and textutil (10.4 text utility). Here's a whole slew of additional utilities, as shown by the command whatis *util* (the trailing * isn't necessary, but who knew if there was some other utility that didn't end with util).
The output you get with the above command looks like this:
drutil(1) - interact with CD/DVD burners escputil(1) - maintain Epson Stylus inkjet printers hdiutil(1) - manipulate disk images mdutil(1) - manage the metadata stores used by Spotlight niutil(1) - NetInfo utility plutil(1) - property list utility smbutil(1) - interface to the SMB requester textutil(1) - text utility textutil(n) - Procedures to manipulate texts and strings tiffutil(1), - tiffutil(1) - manipulates tiff filesNow all you need to do is get the man pages for each of them (the manual for hdutil is very long!) for more info on how they each work.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050706102444691