use FileHandle;

my $log = 0;
print "Do you want to log to a file?";
my $resp = <STDIN>;
if ($resp =~ /^y/i) {
    my $fh = new FileHandle;
    my $filepath = "c:\\stdout.txt";
    $fh->open(">> $filepath") || die "could not open log file $filepath";
    select $fh;
}

#
# this will go to log file if $resp was y
#
print "Holla!\n";