You can also extract a group of characters from a line with the substr function.

  my $mesg = "PMMDF-REC1";
  my $cmd1 = substr $mesg, 0, 1;
  my $cmd2 = substr $mesg, 1, 4;
  my $cmd3 = substr $mesg, 6, 4;

  print $mesg, "\n";
  print $cmd1, "\n";
  print $cmd2, "\n";
  print $cmd3, "\n";
[download]