systemsetup is a great little command, for setting date and time, for wake on LAN, etc. But in Mac OS X 10.6, you can also set your kernel boot architecture? Weird, eh? Not as weird as the length of the option…
systemsetup -getkernelbootarchitecturesetting
Try saying it three times really fast. Now again with a French accent! Anyway, so then you want to set the kernel boot architecture to 32 bit, set it to i386 and if you want to set it to 64 bit, use x86_64 with the -setkernelbootarchitecture option (default is the default value). It edits the com.apple.Boot.plist located at /Library/Preferences/SystemConfiguration/com.apple.Boot.plist.
