Command to swap even and odd numbered lines in a file
 

G'day Gang!

I'm looking for a command to swap the even/odd numbered lines in a file.

Example input file:
Example output file:
I'm sure there's a way to do it with sed, awk, grep and the like but it's been many years since I've used these commands on a daily basis and I can't seem to figure out the correct syntax.

Any help would be greatly appreciated. Thanks!

Maybe something like this:

http://www.gnu.org/manual/gawk/html_...e_002fVariable

LOL. I swear to you I have hunted for days banging my head on that. I knew it would be super simple, which I why I was reluctant to ask about it.

Thanks very much!