I would like to know the ways in which epub files can be converted to pdf in ubuntu. Any method, GUI or command line conversion is fine as far as my epub gets converted to pdf. Thanks.
You definitely want Calibre. You can use it to convert virtually any file type to any other file type, as long as the source file doesn't have DRM (like Amazon, Adobe, etc.). If it does have DRM, check out Apprentice Alf's blog for help stripping it out with Calibre plugins. Don't use the DRM stripper to pirate books or otherwise violate your agreement with the vendor. Use it so you can enjoy your books on any device in any format.
Calibre is also an awesome e-book management program that can do virtually everything. It can manage Kindles, Android phones/tablets, etc. It can even email your books with one click to your Kindle's email address if you want. You won't be disappointed :-)
From a terminal:
sudo apt-get install calibre
Or search for it in Ubuntu Software Center
To actually convert the EPUB file you can use the following command:
ebook-convert file.epub file.pdf (For details, check this other answer)
Or you can check the details for the conversion dialog using the Calibre GUI.
