List of all Environmental Variables

#!/usr/local/bin/perl
# Adjust the above line to find perl on your system

#  test-env.cgi Copyright 1995 by David Efflandt efflandt@xnet.com
#     			May be freely distributed and modified.
#     			Author is not responsible for its use.
#  Note: Variable list will differ if run locally from UNIX

# Print content-type for HTTP/1.0 compatibility
print "Content-type: text/html\n\n";

# Print title and initial heading
print "<Head><Title>Environment</Title></Head>\n";
print "<Body><H1>List of all Environmental Variables</H1><HR>\n";

# Sort and print all environmental variables
foreach $key (sort keys(%ENV)) {print "$key = $ENV{$key}<p>\n";}

# Resolve REMOTE_HOST into name
$ip_address = $ENV{'REMOTE_ADDR'};
@numbers = split(/\./, $ip_address);
$ip_number = pack("C4", @numbers);
($name) = (gethostbyaddr($ip_number, 2))[0];
if (defined $name) {print "<HR>REMOTE_HOST resolves to: $name";}

# Print closing to point to your home page
print "<HR><P>\n";
print 'Return to my <A HREF="index.html">home page</A>.<P></BODY>';
exit;