#!/usr/bin/perl -w
my $all=get_response('a','b');
sub get_response {
  my ($cgi, $CMD) = shift;
  print 'a'.$cgi."\n";  
  print 'b'.$CMD."\n";  
}

##</code><code>##

aa
Use of uninitialized value $CMD in concatenation (.) or string at x1182315.pl line 6.
b

##</code><code>##

sub get_response {
  local %ENV=%ENV; 
  my ($cgi, $query) = @_;
 
  ## prepare proper (CGI) environment
  $ENV{QUERY_STRING} = $query;
  $ENV{REQUEST_METHOD} = 'GET';
  $ENV{GATEWAY_INTERFACE} = 'CGI/1.1';
  # add more as needed
  open(CGI, '-|', $cgi) or die "Can't exec $cgi, $!";
  local $/ = undef;
  my $res = <CGI>;
  close(CGI) or die "Error running $cgi, $!";
  return $res;
}