my $seen = 0; while (<$fh>) { if ( !$seen and m/^alpha$/) { $seen = 'yes indeed'; print "true\n"; }else{ print "false\n"; } } #### foo bar alpha beta gamma delta #### Original: false false true false false false Flipflop: Argument "" isn't numeric in numeric gt (>) at test.pl line 21, <$fh> line 1. false Argument "" isn't numeric in numeric gt (>) at test.pl line 21, <$fh> line 2. false false true true true Flag: false false true false false false