#!/usr/bin/perl -w
use strict;
use warnings;

my $counter=0;
open(DATA, "export.dat")||die "Cannot open export.dat for read:$!\n";
while(<DATA>){

  if (/^1(\d*)/) {
    if ($counter > 0) {
      #No temp file yet if this is the first record
      close TEMP||die "Cannot close temp.dat:$!\n";
         &output_data();
    }
    open(TEMP, ">$temp.dat")||die "Can't open temp.dat:$!\n";
    $counter = 0;
  }

  if (/\S+/) {
    print TEMP $temp_line;
    ++$counter;
  }
}

close DATA||die "Cannot close $in_dir/export.dat (weird):$!\n";
if ($counter > 0) {
  close TEMP||die "Cannot close $in_dir/temp.dat:$!\n";
}

&output_data();

sub output_data{
  #do stuff with temp.dat
}