How to write code in the forums ?

How to write code in the forums ?

Hi all, 
I have been trying to understand how to write code (as in what I'm doing in the terminal) in the fora but there seems to be missing a code thing. In many forums there is a way so it would format the code/commands part differently then all the text. Something like this for e.g. 

http://forums.debian.net/viewtopic.php?f=10&t=74482

Any ideas would be appreciated.