use GraphViz; 
my $g = GraphViz->new(); 
foreach $command (@commands) {
 eval('$g->'.$command);
 } 

##</code><code>##

use strict;
use CGI;
my @comm = ("header('first')","header('second')");
my $cgi = new CGI;
foreach my $comm (@comm) {
    eval('print $cgi->'.$comm);
}

##</code><code>##

Content-Type: first

Content-Type: second

##</code><code>##

my $comm = "header";
print $cgi->$comm('third');

##</code><code>##

 my $comm = "header('third')";
 print $cgi->$comm