my $dir = 'D:\\tmp\\prog\\math\\lp32'; my $lp_solve = "d:\\mydir\\lp_solve.exe"; my $lpfile = "d:\\mydir\\model.lp"; (my $lp = << " EOF") =~ s/^\s+//gm; min: 8 x1 + 15 x2 ; c1: 10 x1 + 21 x2 > 156 ; c2: 2 x1 + x2 > 22 ; EOF open OUTFILE, "+>$lpfile"; print OUTFILE $lp; close OUTFILE; $output = qx($lp_solve < $lpfile); $output =~ s/\r//gm; print $lp; print $output; system("del $lpfile");