Originally Posted by damlays
But I need the file will be backed up triggered by every new upload.
How is the file uploaded? - FTP or a HTTP upload?
If its FTP then the most you're going to get is a cycling script that cycles for say 59 seconds before quitting and being restarted by a cron.
If you have total control of the system and can run scripts indefinitely then you could write a service that will just run continually checking for new files and saving them otherwise you're stuck with the 59 seconds and a new cron instance scenario.