#!/usr/bin/perl
 
@log = <STDIN>;
$log = join '', @log;
while ($log =~ m/(\d+\.\d+\.\d+\.\d+\s)/g)
{
	$ip = $1;
	chomp $ip;
	$count = ($log =~ s/$1/$1/g);
	print "$ip $count\n";
}

$ time cat ipaddr.txt | perl count.pl > report.txt

real	4m9.138s
user	3m7.281s
sys	0m58.301s

#!/usr/bin/perl
 
@log = <STDIN>;
$log = join '', @log;
while ($log =~ m/(\d+\.\d+\.\d+\.\d+\s)/g)
{
	$ip = $1;
	chomp $ip;
	++ $count{$ip};
}
foreach $ip (keys %count)
{
	print "$ip $count{$ip}\n";	
}

$ time cat ipaddr.txt | perl hashcount.pl > report.txt

real	0m0.501s
user	0m0.433s
sys	0m0.052s