Where are the /dev folder and the /dev/null device located on Mac OS X Mountain Lion? I am trying to find them on my Mac OS X Mountain Lion and it seems they do not exist. 
I do not think it is a problem of folders privileges.

Maybe it just doesn't exit and I have to create them.
It should be there as a character special file:

bash-3.2# cd /dev
bash-3.2# ls -l |grep null
crw-rw-rw-  1 root  wheel       3,   2 Mar  8 11:04 null


Finder doesn't show these folders so you need to be in terminal to see them.