Oh, cat [source] > [destination] works too. I mentioned it because it's always been built into the shell, and I don't think cp was always built-in. I remember at one time I couldn't use cp but I was always able to use cat, and since they both work identically for copying (you just need that right arrow in the command), I always suggest cat just to make sure more people can follow the directions.
See, it says:
Concatenate two files:
$ cat file1.txt file2.txt > union.txt
But if you just put one file as the source, it "combines" that one file into the new file, which is essentially copying.