Sioyek is a free and open source PDF viewer for Linux, Windows and MacOS. It is released under GNU General Public License v3.0. It is a minimal but powerful PDF viewer. You can control Sioyek via keyboard with keybindings. You can change the default keybindings by editing keys_user.config file. This app is specially designed for reading research papers and technical books. For the complete usage details click here.
How to Install Sioyek PDF Viewer on Ubuntu Linux
Download Sioyek in portable AppImage from the above download link and save it on your Downloads folder. Here the downloaded file name is “sioyek-release-linux.zip” . Right click on it and select Extract Here option. Now open the extracted sioyek-release-linux folder and you will get “Sioyek-x86_64.AppImage” file. Right click on it and select Properties->Permissions tab and check Allow executing file as Program option and close the window.
Now right click on Sioyek-x86_64.AppImage file and select Run to start Sioyek PDF Viewer.
Install Sioyek PDF Viewer via Flatpak:
Sioyek is available as a flatpak package from remote flathub. So you need to install flatpak and flathub on your system and restart your system after the installation. After that open the terminal app (ctrl+alt+t) and run below Sioyek flatpak installlation command.
flatpak install flathub com.github.ahrm.sioyek
After the installation open Sioyek using below flatpak command.
flatpak run com.github.ahrm.sioyek
You can also uninstall it using this command.
sudo flatpak uninstall com.github.ahrm.sioyek