Various editors exist for Unix operating systems. A common editor for beginners is Pico. It is easy to use and simple, although less powerful than other editors. Emacs38 and VI39 are the two editors typically used by experienced Unix users.
Both Emacs and VI are extremely powerful and available on almost all Unix systems. For more information on Unix editors browse the web -- there are many very good FAQs available.
If you invoke an editor you are unfamiliar with or unable to use, the key sequences in table 4 may be used to exit without writing any changes to disk.