How to duplicate a line?

[Kai Großjohann]

Say I have a file which contains the line

    Media: a4 1 2 3 4 5 6 7

And I want to copy this line and modify the copy slightly so that I
end up with the following two lines

    Media: a4 1 2 3 4 5 6 7
    Media: A4 1 2 3 4 5 6 7

How would I go about this?  I don't want to hardwire the "A4" line in
my script, instead it should be taken from the file.
-- 
Ambibibentists unite!