This could be a useful if you are wondering the solution with minimal number of lines. 
open( INPUTFILE, "<WordNet.txt" ) or die "$!";

open( OUTPUTFILE, ">>WordNetTest2.txt" ) or die "$!";

grep {  /adj:/ and print OUTPUTFILE $prev,$_;$prev=$_  } (<INPUTFILE>)
+;

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In reply to Re: Using grep to pick out lines in a text file by balakrishnan
in thread Using grep to pick out lines in a text file by Bunta

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