title: Append/concatenate two files using spark/scala
body: <p>I have multiple files stored in HDFS, and I need to merge them into one file using spark. However, because this operation is done frequently (every hour). I need to append those multiple files to the source file.</p>
  
  <p>I found that there is the FileUtil that gives the 'copymerge' function. but it doesn't allow to append two files. </p>
  
  <p>Thank you for your help</p>