#!/usr/bin/perl

use CGI;
use IO::File;
use POSIX;
use strict;

my $cgi = CGI->new;

#   temporary file name is supplied by POSIX::tmpnam function
my $buffer;
my $tmpfile = POSIX::tmpnam;

#   loop through CGI handle and write new temporary file
my $fh = IO::File->new(">".$tmpfile);
print $fh $buffer while (read($cgi->param('inputfile'), $buffer, 1024));
$fh->close;

#   retrieve file name from CGI file field parameter
my $newfile = ($cgi->param('inputfile') =~ /^((?:.*[:\\\/])?)(.*)/s)[1];

#   rename file unless file exists
rename $tmpfile, $newfile unless -e $newfile;

#   return HTML headers and page data

.
.

exit 0;