Bad Binary?

[Checkmate]

Ok, as I'm fairly new to Linux, I am having a wonderful time trying to figure out all the commands. So I found this command: sudo -s mkdir /home/cache

Then when I type that out in terminal I get the following error:
"/bin/mkdir: /bin/mkdir: cannot execute binary file"

So how or what am I doing wrong here?

OS: Ubuntu 8.10 (Intrepid)
Netbook eeePC901

[14049752]

Out of curiousity, what do you get when you take out the "-s"? Ubuntu doesn't really support the -s (su command)

[Checkmate]

LOL all these flavors of Linux... gotta love it. Thanks 140, that did it.