cmd1 arg1 arg2 2>cmd1.log | cmd2 arg1 2>cmd2.log | cmd3 2>cmd3.log

##</code><code>##

execute_cmd(cmd1, @args, $in_fh1, $out_fh1, $err_fh1);
execute_cmd(cmd2, @args, $in_fh2, $out_fh2, $err_fh2);

while (<$out_fh1>) {
  print $in_fh2 $_;
}