Quick and dirty way to split varnish log stream into separate file.

sessionlog.pl

use IO::File;
while($logline = <>) {
    ($n) = $logline =~ m/\s+(\d+)/;
    unless ($F{$n}) {
        print "New FD: $n\n";
        $F{$n} = IO::File->new("$n.log", "w")
    };
    $F{$n}->print($logline);
}