Jeff discusses his back-and-forth on comfort with operating systems. I don’t have any advice to give regarding the iBook and OSX, but you can grab Cygwin and get a nice bash shell along with lots of other goodies. (Not that I want to dissuade anyone from using Unix, but most of the time we have better things to do than learn the ropes of another OS…)
Update: Of course, I missed Jeff's original reference to Cygwin, but he explains here why he doesn't like it.