find program for a file

edit

You can use dnf to query mimetypes

$ sudo dnf repoquery --whatprovides 'mimehandler(application/*epub*)'
Last metadata expiration check: 1:27:35 ago on Sun May 29 12:21:50 2016.
atril-0:1.14.1-1.fc24.x86_64
calibre-0:2.56.0-1.fc24.x86_64
kchmviewer-0:7.5-3.fc24.x86_64
okular-0:16.04.1-1.fc24.x86_64
sigil-0:0.9.3-1.fc24.x86_64

As noted by @Aeyoun - you can use the search feature of GNOME Software, which will hopefully give you a match of one or more applications that you can use for that file type. Install and remove applications, as appropriate, to try the different suggestions.

Using the command-line:

• Use sudo dnf search epub (replace epub with some other keyword or file extension to find other suitable applications).
• Use sudo dnf search '*KEYWORD*' to search for a word using globbing (the '*').
• Use sudo dnf search all '*KEYWORD*' to include searching the full description and URLs as well.
• Use sudo dnf info PACKAGE-NAME to find out more about the application - usually including URLs that allow you to investigate the app further.

You can review apps that are already installed, that may be of use, by using man -k KEYWORD

You can use the GNOME Software center thingy. It’s installed by default and you can find it in the application list by searching for “software” or “app store”.

The program you’ll want for ePubs is Calibre. GNOME Books looks like an interesting option, but trust me – it’s really broken and the project appears abandoned.