Main
---------------------------------------------------------    
 sub1         sub2           sub3       sub4
--------------------------------------------------------  
sub11         sub21         sub31       sub41                   
sub12         sub22         sub32       sub42
sub13         sub23         sub33       sub43
___________________-____________________________________

##</code><code>##

Main
sub1
sub11
sub12
sub13

##</code><code>##


sub2
sub21
sub22
sub23

##</code><code>##

sub3
sub31
sub32
sub33

##</code><code>##

#! /usr/bin/perl
@listofLinks=qw(Main)
&fileview

sub fileview
{
  @listLinks=@_;
  #print @listLinks;
  foreach $val (@listLinks)
  {
     
       if ($count<2)
       {

          $count++;
          @newlinks=getlinks($val);
          &fileview(@newlinks);
       }
      &printFile($val);
         
       }
  }
  $count--;
  last if($count==0);
}

sub getlinks
{
$file=$_[0];
open (FH,$file);
@arr=<FH>;
return(@arr);
}
sub printFile
{
open(FH,"$_[0]");
@arr=<FH>;
print "@arr\n";
}