You now have an ugly rhyme developing with the use of the ls command. To delete a file, use the rm command. (``rm'' stands for ``remove'').
/home/larry/foo# rm bells sells
/home/larry/foo# ls -F
shells
/home/larry/foo#
We're left with nothing but shells, but we won't complain. Note that rm by default won't prompt you before deleting a file---so be careful.
A related command to rm is rmdir. This command deletes a directory, but only if the directory is empty. If the directory contains any files or subdirectories, rmdir will complain.