question: private int append ( FileSystem fs , Configuration conf , Path src , PrintWriter writer , int currentRecordNumber ) throws IOException { BufferedReader reader = new BufferedReader ( new InputStreamReader ( fs . open ( src ) ) ) ; try { String line = reader . readLine ( ) ; while ( line != null ) { if ( line . startsWith ( "Recno:: " ) ) { line = "Recno:: " + currentRecordNumber ++ ; } writer . println ( line ) ; line = reader . readLine ( ) ; } return currentRecordNumber ; } finally { reader . close ( ) ; } }
target:  Appends two files and updates the Recno counter 