Help About Terminal!

i have store some files in macintosh HD (the icon on the desk)/computer science/hello.
then i startup the terminal, and i type "ls" and other commands, but i still can not access there(macintosh HD (the icon on the desk)/info/hello.)
How can i access that file named hello, when i am using termianl, thX

When you open a new terminal window, the directory it is set to by default is your user's home directory. If you want to go up a directory, type "cd .." - that will take you to the Macintosh HD/Users folder. Type it again and you'll get to Macintosh HD. From there you should be able to type 'ls' and see your computer science folder there. Type cd "computer science"/hello to get to your 'hello' directory.

However, I suggest you move your files to your user's directory somewhere (maybe documents?) if you don't want other users to be able to access the files.

You can also type "cd /" to get to the root of the drive and go from there.

i thought cd ment "change directory"

Yes, it does. If you type cd without any arguments then it'll take you to your home folder. Basically the format is "cd directory/subdirectory"