open (REFFILE,"$reffile") || print "Content-type: text/html\n\n Can't Open $reffile(r): $!\n";
my(@LINES)=<REFFILE>;
close(REFFILE);
$SIZE=@LINES;
open (REFFILE,">$reffile") || print "Content-type: text/html\n\n Can't Open $reffile(r): $!\n";
print REFFILE "$date\| $ENV{'REMOTE_HOST'}\| $ENV{'HTTP_USER_AGENT'}\|$FORM{'discnt'}\|$FORM{'shipcountry'}\|\n";

##</code><code>##

my $htmlheader = "Content-type: text/html\n\n";
open (REFFILE, '<', $reffile) || print "$htmlheader Can't Open $reffile(r): $!\n";
[...]
open (REFFILE, '>', $reffile) || print "$htmlheader Can't Open $reffile(r): $!\n";

##</code><code>##

close(REFFILE)
  || print "$htmlheader Can't close filehandle for $reffile(r): $!\n";
[...]
print (REFFILE "$date\| $ENV{'REMOTE_HOST'}\| $ENV{'HTTP_USER_AGENT'}\|$FORM{'discnt'}\|$FORM{'shipcountry'}\|\n")
  || "$htmlheader Can't write to $reffile(r): $!\n";

##</code><code>##

my $htmlheader = "Content-type: text/html\n\n";
open REFFILE, '<', $reffile
  or print "$htmlheader Can't Open $reffile(r): $!\n";
my(@LINES)=<REFFILE>;
close REFFILE
  or print "$htmlheader Can't close filehandle for $reffile(r): $!\n";
$SIZE=@LINES;
open REFFILE, '>', $reffile
  or print "$htmlheader Can't Open $reffile(r): $!\n";
print REFFILE "$date\| $ENV{'REMOTE_HOST'}\| $ENV{'HTTP_USER_AGENT'}\|$FORM{'discnt'}\|$FORM{'shipcountry'}\|\n"
  or "$htmlheader Can't write to $reffile(r): $!\n";;

##</code><code>##

my $htmlheader = "Content-type: text/html\n\n";
open my $fh_read, '<', $reffile
  or print "$htmlheader Can't Open $reffile(r): $!\n";
my(@LINES)=<$fh_read>;
close $fh_read
  or print "$htmlheader Can't close filehandle for $reffile(r): $!\n";
$SIZE=@LINES;
open $fh_write, '>', $reffile
  or print "$htmlheader Can't Open $reffile(r): $!\n";
print {$fh_write} "$date\| $ENV{'REMOTE_HOST'}\| $ENV{'HTTP_USER_AGENT'}\|$FORM{'discnt'}\|$FORM{'shipcountry'}\|\n"
  or "$htmlheader Can't write to $reffile(r): $!\n";

##</code><code>##

my $shipcountry;
# shipcountry may contain letters, digits, underscores, spaces and dashes
# and nothing else
if ($FORM{'shipcountry'} =~ /^([\w -]+)$/) {
  $shipcountry = $1;
}
else {
  print "$htmlheader Invalid input for shipping country detected!\n";
}
print {$fh_write} "$date\| $ENV{'REMOTE_HOST'}\| $ENV{'HTTP_USER_AGENT'}\|$FORM{'discnt'}\|$shipcountry\|\n"
  or "$htmlheader Can't write to $reffile(r): $!\n";