title: SharePoint Online : Overwrite a content of file in Document Library using CSOM
body: <p>I have a document library which is consists of different files. I have a task to Read all the files and overwrite the content in it and Upload back to the SharePoibnt online.</p>
  
  <p>I need to do this as a migration process and must be done in AppUpgraded.</p>
  
  <p>I tried with file.SaveBinary(write.ToArray()) , it pass the code but did not update the file data.</p>
  
  <p>Example will be appreciated.</p>