use strict;
use warnings;

my $num      = 1;
my $recLines = 2;

while (!eof DATA) {
    ## Open the file once every iteration
    my $outfile = sprintf("Int_%s.txt", $num);

    print "---> Create file $outfile\n";
    printf("%-1s%-12s%-8s%-4s%-4s%-10s%-33s\n",
        "H", $outfile, "20101221", "1230", $num, $., " ");

    for (1 .. $recLines) {
        last if eof DATA;
        last if ! defined (my $line = <DATA>);

        print $line;
    }
    printf("%-1s%-12s%-8s%-4s%-4s%-10s%-33s\n",
        "T", $outfile, "20101221", "1230", $num, $., " ");
    print "<--- Close file $outfile\n";
    ++$num;
}

__DATA__
1234567|HP|GASS
1234567|TP|GASS
3456789|YU|GASS
3245678|TY|GASS

##</code><code>##

---> Create file Int_1.txt
HInt_1.txt   2010122112301   0                                          
1234567|HP|GASS
1234567|TP|GASS
TInt_1.txt   2010122112301   2                                          
<--- Close file Int_1.txt
---> Create file Int_2.txt
HInt_2.txt   2010122112302   2                                          
3456789|YU|GASS
3245678|TY|GASS
TInt_2.txt   2010122112302   4                                          
<--- Close file Int_2.txt

##</code><code>##

# input handle:
open my $inFile, '<' $source or die "Can't open '$source' $!";

# output handle:
open my $outFile, '>' $target or die "Can't open '$target' $!";