use Data::Dumper;

my $q = CGI->new();
my %var = $q->Vars();

my $log_file = 'log.txt';

open(LOG,">>$log_file") || err("Can't open log file: $!");
print LOG "URL: $ENV{REQUEST_URI}\n\n",
          Dumper(\%var,\%ENV)."\n\n",
          '=' x 60,
          "\n\n";
close LOG;