#!/usr/bin/perl -w
use strict;

my @emailaddr;

while (<DATA>)
{
  if (/@/)  #skip lines without email addresses
  {
     push (@emailaddr, $_) foreach /[\w@.]+/g; 
  }
}

my %seen;
@emailaddr = grep { !$seen{(split(/[@]/,$_))[0]}++}@emailaddr;

print join(',',@emailaddr),"\n";

#output line
#alay@nkk.com,brps@nkk.com,luin@nkk.com,sthn@nkk.com,toen@nkk.com,mara@nkk.com,wnrd@nkk.com,jpnd@ckk.com,Daim@nkk.com,nbic@ckk.com,nbrs@crawford.com,nbc1@Ckk.com,jodo@nkk.com,trrt@nkk.com,alam@mkk.com,Case@nkk.com,miob@ikk.com,JTny@ikk.com,RBwn@ikk.com,jsab@ikk.com,Shli@nkk.com,Stee@nkk.com,Eron@nkk.com

__DATA__
                                                                                                  argument_value                                                                                                                                                                                                       
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 alay@nkk.com
 brps@nkk.com, luin@nkk.com
 sthn@nkk.com

 toen@nkk.com

 mara@nkk.com

 alay@nbkk.com
 wnrd@nkk.com, jpnd@ckk.com, Daim@nkk.com, nbic@ckk.com, nbrs@crawford.com, nbc1@Ckk.com,jodo@nkk.com, mara@nkk.com

 trrt@nkk.com
 alay@nkk.com
 alam@mkk.com, Case@nkk.com, miob@ikk.com, JTny@ikk.com, RBwn@ikk.com, jsab@ikk.com, Shli@nkk.com, Stee@nkk.com, Eron@nkk.com