use Tie::File;
my $filename = 'thelog.log'
tie my @array, 'Tie::File', $filename 
    or die "can't open file:$filename : $!";

for my $i ( 0 .. $#array )
{
    my $line = $array[$i];
    if ( $line =~ m/MYLOGREGEX/x )
    {
         my $date = $array[ $i - 8 ];
         ## do something with $line and $date
    }

}