Actually, that's not quite accurate. According to what I read, the while loop looks like this:

LINE:
    while (<>) {
        # your code goes here
    } continue {
        print or die "-p destination: $!\n"; 
    }
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A continue block gets executed the instant before the loop condition is evaluated. So 'redo' does not cause the continue block to execute, but 'next' does, and a normal iteration of the loop causes the continue block to execute as well.

This works for me:

perl -pe 'if($_ eq "\n"){$n=1;next;} if($n){$n=0;next;}else{s/# file/\
+n# file/;}' data1.txt
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