while () { if (/regular files|archdone files/) { local $, = "\n"; s/,//; print +(split)[2], $,; $diff[++$i] = (split)[2]; } } print $diff[1]-$diff[2],"\n"; __DATA__ regular files 62,622 597.488G 641547379187 archdone files 62,535 597.008G 641032761295