foreach my $filename (reverse((grep /^sniffer/, <*>))) 
{
    my $new_name = $filename;
    
    if($new_name =~ m/(\d+)/)
    {
    	my $value = $1 +1;    	
    	$new_name = "sniffer$value.log";      	
    }
    else
    {
    	$new_name = "sniffer1.log";
    }
rename($filename, $new_name) unless $filename eq $new_name;
    
}