sub mergeLogs()
{
    my $day = shift;
    my @files = @_;
    my @lines;

    foreach my $file (@files)
    {
        my $fh = &openLogFile($file);

        if (! defined $fh)
        {
            warn "$0: ignoring file $file\n";
            next;
        }

        warn "-> processing $file\n" if $opts{'verbose'} > 0;

        push @lines, map { &filterLog($_) } grep { /Running|Dump|FromCB|Update/o } <$fh>;
        close $fh;
    }

    @lines =    map { $_->[0] }
                sort { $a->[1] cmp $b->[1] }
                map { [ $_, /(\d{2}:\d{2}:\d{2}\.\d{3})/o ] } @lines;

    return \@lines;
}

sub filterLog()
{
    my $line = shift;

    $line =~ s/ {2,}/ /g;
    $line =~ s/^((?:\S+ ){3}).+?\[?I\]?:/$1/;
    $line =~ s/ ?: / /g;
    $line =~ s/ ACK (\w) / $1 ACK /;

    return unless ! exists $opts{'day'} || /^$opts{'day'}/o;
    return unless ! exists $opts{'user'} || /[\(\[]\s*(?:$opts{'user'})/o;

    if (exists $opts{'start-time'} || exists $opts{'stop-time'})
    {
        if ($line =~ /(\d{2}:\d{2}:\d{2}\.\d{3})/o)
        {
            return unless ! exists $opts{'start-time'} || $opts{'start-time'} lt $1;
            return unless ! exists $opts{'stop-time'} || $opts{'stop-time'} gt $1;
        }
    }

    warn $line if $opts{'verbose'} > 3;

    return $line;
}