$ perl -wMstrict -le 'print join(" ",map {int(rand(100))-50} 0..rand(7)+3) for 1..1000000' >in.txt $ wc -l in.txt 1000000 in.txt $ head -5 in.txt -49 43 0 -35 0 -20 -49 5 46 -11 -14 39 39 -24 -49 36 -7 -36 -43 15 30 5 -4 11 37 -25 27 -49 21 49 33 -15 -16 17 10 32 -14 -30 $ time perl 1190600.pl in.txt >out.txt real 0m1.869s user 0m1.863s sys 0m0.004s $ time perl 1190602.pl in.txt >out.txt real 0m1.539s user 0m1.521s sys 0m0.016s