I don't think that accomplishes the goal.

It depends upon which of the stated goals you focus on. The op's description started with

I have a unix-formatted double spaced file, so each line of text is followed by 2 linefeeds,...

And if that is an accurate statement of the problem, my one-liner will work.

If it's not accurate, or omits significant details, then it won't and a slightly more sophisticated one-liner is required: 

perl -e"BEGIN{$/=qq[\n\n]}" -ne"chop;print" junk.txt

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In reply to Re^3:how to use matching operator on newlines by BrowserUk
in thread how to use matching operator on newlines by redss

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