It's been a long time since I've played DOOM. Heard of DOOM III coming out
and took an interest again. I used to have a couple of books that had the
cheat codes but have lost the books many years ago, and all I can remember
is:

IDBEHOLD(x)
IDKFA
IDDT

Could someone please post any additional codes I've forgotten. Mainly the
one that lets you pass through walls and also the one that kicks you up to
200% health.

Thanks,
Sarumen