Thank you gents. I thought this was an especially unclear passage, as blakem pointed out. It might be correct if the author means  print "${system('rm -rf')}"; is bad but that would be your own dumb fault wouldn't it? And what would that have to do with taint?

Well, any way, thanks for your clarity and wisdom.

Ira,

"So... What do all these little arrows mean?"
~unknown