my @member = $entry->get_value ('memberOf');
 my @memberof = grep(/\CN=ext\.Group\.([^,]+)/,@member);
  $member = join(',',@memberof);
  
 print "$uid -- $member\n"; 

##</code><code>##

Michael Douglas -- CN=ext.Group.eso,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local,CN=ext.Group.test,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local,CN=ext.Group.test1,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local,CN=ext.Group.test2,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local
 

##</code><code>##

Michael Douglas -- eso, test, test1, test2