open (DATA, "test.txt") || die "Unable to open file: $!";
open (OUT, ">testout.txt") || die "Cannot create out file: $!";
while (<DATA>) {
    print OUT "\n" if /^10/; print OUT;
}
close (DATA) || die "Unable to close file: $!"; 
close (OUT) || die "Unable to close file: $!";
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