use Time::HiRes qw/ gettimeofday /;
use strict;
my $starttime = gettimeofday;

open OUTFILE, ">file.txt" or die $!;
for (1 .. 554152) {
	print OUTFILE "X"x100, "\n";
}
close OUTFILE;

print "Creating file took ", gettimeofday - $starttime, " seconds\n";

$starttime = gettimeofday;

open INFILE, "<file.txt" or die $!;
open OUTFILE, ">file1.txt" or die $!;
while (<INFILE>) {
	chomp;
	print OUTFILE join (",",  /(.{,10})/g), "\n"
}

print "Splitting file using regexp took ", gettimeofday - $starttime, " seconds\n";

__OUTPUT__

Creating file took 8.515625 seconds
Splitting file using regexp took 1.5 seconds