The ePub container is just a ZIP file with standard compression, except that the file mimetype must be first and must not be compressed.
So, to "explode" an .epub file all you need is any command or utility that extracts files from a ZIP. To "implode" (is there a better term for this?) it back to a .epub isn't quite as easy. Salty-horse provides a Unix command line "implode" procedure here
. Since it is using Info-ZIP
, something similar should work for the Windows command line and on a Mac.
Is there a better 1-step, or GUI-based, method to do this?
Note that the contents of an ePub are fairly rigidly defined, and an explode/implode tool does nothing to check the validity of the contents (I guess the implode could check that the mimetype file exists and had the right contents, or make one if there is none). As in salty-horse's example, it would be most useful when something is wrong with an existing DRM-free ePub and you want to fix it.