I found Level 8 quite hard and took me awhile to work out the command, had to learn unix command, of which was a good thing. Anyway to get pass level 9 is quite easy and you will be kicking yourself when you work it out.
I hope this is not a spoiler, if so please edit, I am just trying to help people learn.
Anyway go back to level 8 and study the command you used to gain access to the files.
Read this link about Unix commands : http://www.computerhope.com/unix/uls.htm
Finally think "How do I move between dirs using CMD??"
Hope this helps... stuck on level 10 at moment!