#!/usr/bin/perl -w;
open IN, "file.in" or die "file.in: $!";
open OUT, ">file.out" or die ">file.out: $!"
while (<IN>) {
  if ($_ =~ /^\d/) {
    print OUT $_;
  }
}
close IN;
close OUT;

##</code><code>##

#!/usr/bin/perl -ni.bak
if ($_ =~ /^\d/) {
  print $_;
}