i need to split a large file into smaller files

Based on your criteria here is yet another solution:

#!/usr/bin/perl -w
#########################################################
 
use strict;
use Tie::File;
 
my @fin=();
my @fout=();
 
tie @fin,"Tie::File","bigfile.txt" or die $!;
my $fcount=1;
for(my $ix=0;$ix<=$#fin;$ix+=30){
    my $end = ( $ix+29 <=$#fin ? $ix+29 : $#fin );
    my $outfilename = sprintf("litte_file_%0.2d.txt",$fcount);
    tie @fout,"Tie::File",$outfilename or die $!;
    for(my $iy=$ix;$iy<=$end;$iy++){
        push @fout,$fin[$iy];
    }
    untie @fout;
    $fcount++;
}
[download]

[pberghol@cowdawg splitter]$ wc -l bigfile.txt
    500 bigfile.txt
[pberghol@cowdawg splitter]$ wc -l litte_file_*
     30 litte_file_01.txt
     30 litte_file_02.txt
     30 litte_file_03.txt
     30 litte_file_04.txt
     30 litte_file_05.txt
     30 litte_file_06.txt
     30 litte_file_07.txt
     30 litte_file_08.txt
     30 litte_file_09.txt
     30 litte_file_10.txt
     30 litte_file_11.txt
     30 litte_file_12.txt
     30 litte_file_13.txt
     30 litte_file_14.txt
     30 litte_file_15.txt
     30 litte_file_16.txt
     20 litte_file_17.txt
    500 total
[download]