since no single line contains the sentance, you don't need to be doing the test inside the while loop.

@current_spurt always has only one word in it.

just have another array called @my_sentance, and push @current_spurt on it. after the while loop where you read and process the file, do your if /\bso\b test.

I modified:

        print STDOUT $string if $yeah;
        print $string;

# into
        print STDOUT $string if $yeah;
        print $string, "|$.|";
# $. is the current line input number, see perlvar for more


# and got

bash-2.05$ perl test.org.pl ./data/ out
|2||3||4|<s> so <s> so |5|we |6|can |7|do |8|it |9|again |10|yeah |11|
+yeah </s>
|12||13|bash-2.05$
bash-2.05$
[download]

 
___crazyinsomniac_______________________________________
Disclaimer: Don't blame. It came from inside the void
perl -e "$q=$_;map({chr unpack qq;H*;,$_}split(q;;,q*H*));print;$q/$q;"