Emacs and Vi are too bloated. If you must use a utility to compose text files in unix, there is a perfectly usable and full featured word processor right there in /bin on every POSIX compliant system.

I speak of the Computer Aided Text processor

It has a few command line options depending on whether you want your lines numbered, reduce unnecessary whitespace, and other conveniences. Each line is fully editable until you commit it by hitting the enter key. If something happens while you're typing it, not to worry: it autosaves after each line of text. Just use the -a (append) option when you run it again to finish the file.

You only need to remember one control sequence. Unlike those wannabe window managers like emacs and vi with their scores of non-mnemonic commands. When you're done typing in cat, hit ctrl-d (for done, of course) and that's it.