use CGI qw(:standard);
use File::Basename;

my $PATH = '/path/to/dir/to/store/files';

if (param('go')) {
   my $handle = upload('the_file');

   my $name = param('the_file');
   fileparse_set_fstype('MSDOS') if $name =~ /\\/;
   $name = basename($name);

   open OUT, '>', "$PATH/$name" or die "can't open file $name: $!";
   print OUT while <$handle>;
}