Ever wanted to add something to the top of a file in UNIX?
Say, the date?
You could:

ex - file << END
%!date && cat
w
END

Blammo! The date is now at the top of file.

Isn't that nicer than:
date >> newfile && cat file >> newfile && mv newfile file


So, if you want to add text (rather than the output of a command such as date):
ex - file << END
%!echo "This is a lot of text to add" && cat
w
END