If you insist on doing it the command-line way, here’s how: First, copy the kext file to /System/Library/Extensions. Then, open the Terminal app (located in OS X under Applications->Utilities) and type:
cd /System/Library/Extensions
For those unfamiliar with command line, this just changes the directory that Terminal is working on to /System/Library/Extensions. Then type:
sudo chmod -R 755 name.kext
sudo chown -R root:wheel name.kext
Replace “name.kext” with the name of the kext you’re installing. This fixes the kext’s permissions (basically what System Utilities does in Multibeast). If you’re running Mac OS X Lion, this is all you need to do. If you’re still running Snow Leopard, you also need to clear the kernel cache. Type in this:
sudo rm -R Extensions.kextcache
sudo rm -R Extensions.mkext
sudo rm -R Extensions.mkext
