if you google "man cp" it will give you sites with the manual page (man) of the copy (cp) command. On ubuntu, typing "man cp" will give you the same thing, but not in maemo (documentation stripped for space saving).
You may also need "ls" to know the permissions of files, and "chown" to change them.

But in general if you google "linux command line <what I want to do>" you should easily find the command you need.