Since Ubuntu is a Linux operating system, you can bypass the graphical user interface entirely and open your PDF files from the command line.

Discover beginner-friendly Linux command-line tools that can boost your productivity, simplify tasks, and make your terminal workflow more efficient.

In the download: Linux 101: How to give users sudo privileges on Ubuntu and Red Hat-based Linux distributions Linux 101: How to search for files from the Linux command line ...

LFCS: Essential Commands (Ubuntu) is authored by Scott Simpson, who has also designed a number of Linux courses pertaining to system maintenance, building a home server and file sharing.