(Hint: blindly using my docker image is only slightly better from a security perspective. What you _should_ do is download the dockerfile, audit it carefully, and then create your own docker image. And then you're _still_ trusting the Calibre folks to have access to your X server....)
sudo -v && wget -nv -O- https://download.calibre-ebook.com/linux-installer.py | sudo python -c "import sys; main=lambda:sys.stderr.write('Download failed\n'); exec(sys.stdin.read()); main()"
Or you can trust my docker image, where I've done this for you:
https://hub.docker.com/r/tytso/calibre/
(Hint: blindly using my docker image is only slightly better from a security perspective. What you _should_ do is download the dockerfile, audit it carefully, and then create your own docker image. And then you're _still_ trusting the Calibre folks to have access to your X server....)