Calibre ➹

Calibre is, in the author’s own words, meant to be a complete e-library solution and thus includes library management, format conversion, news feeds to ebook conversion, as well as e-book reader sync features and an integrated e-book viewer.

This is what it used to look like when I started using it in 2009 (it now looks much better, even if definitely not native under macOS):

It is Python-based and runs on Linux, Mac OS X and Windows, and supports pretty much any e-book reader out there.

Running a built-in recipe from the command line and e-mailing it to your Kindle:

ebook-convert "The Economist (RSS)".recipe /tmp/economist.mobi
echo | mutt -s "The Economist (RSS)" -a /tmp/economist.mobi -- [email protected]

Use ebook-convert —list-recipes to get a list of the built-in recipes or use a custom .recipe file as argument. Also, if you need PDF output or SVG processing, you need to have Qt installed and (if you’re using a headless server) set up Xvfb or similar.

(You can do that trivially by doing xvfb-run ebook-convert….)