Cloud9 IDE provides the usual file handling features you have come to expect from an IDE. Let's take a look at the File menu and explore the options:

The Revert to Saved option allows you to revert your file to its last saved version.

The Save functions (Save, Save As and Save All) allow you to: a) save the file you are currently working on (Save), b) save your current file with a different name and/or in a different location (Save As ...) and c) save all your open file (Save All). 

As you might expect, the Open Recent option allows you to reopen you recently closed files from a menu.

The New functions (New File, New from Template and New Folder) also offer the expected functionality, with New from Template presenting you with a menu with several options of file template to choose from.

You can see Cloud9 IDE's file handling functionality in action in the following video.