[HAL9000]

My father-in-law is an absolute cheap skate, but fairly patient with techie stuff. I can hand build a cheap PC for less than even a MAC mini (which didn't exist when he got his system.)

If he knows how to work the basic commands like cd, cp, vi, man, grep, regular expressions, etc. - and he doesn't care about the awful GUI - Linux is okay.

But it's downright cruel to make a typical father-in-law use Linux.

[ThePythonicCow]

Good grief - you are confusing the choice of GUI versus command line with the choice of Linux versus Windows.

My father-in-law has no clue how to use the command line commands such as cp, vi, man, grep or whatever.

He runs a gui (KDE, in a SuSE distro), just like most Mac and Windows users to.

On the other hand, one can run a command line shell on Mac (quite useable, since its GNU/BSD based) or Windows (a rather odd combination, though 4DOS/4NT from JPSoftware makes it tolerable, and for a while was my favorite tool.)

[zeugma]

But it's downright cruel to make a typical father-in-law use Linux.

I don't know about that. I converted my mother-in-law to Linux, and I actually like her. :-)  She's been fairly happy with it so far. much happier than when she ran MS-Windows anyway.