Hi usertest,

Please use <code> tags to format your input and output - see How do I post a question effectively?

There are several ways to do this, here's a quick oneliner using the input record separator and a regex:

perl -wne 'BEGIN{$/=qq{\nEND\n}} print unless /^START$ .* ^def$/xms;' 
+input.txt
[download]

Note that this is a little simplistic and will also print data which is outside of the START...END markers.

Hope this helps,
-- Hauke D