foreach $file ( sort keys %csv_data ) { #file SCVG_ACE.txt
      foreach $item ( %{$csv_data{$file} }) { #item 13304_21114.01
		if (exists($csv_data{$file}{$item})){ #if the item is found again add the filename to the 
		#first element of the value
			 $csv_data{$file}{$item} = s/^([^\|]*)\|/$1\/$file\|$csv_data{$file}{$item}/;
						
		} else {
			# maintain the normal data 
		}
	  }
}