Okular is a free and open-source multiplatform document viewer developed by the KDE community and based on Qt and KDE Frameworks libraries. The document viewer is distributed as part of the KDE Applications bundle. Its origins are from KPDF, and it replaces KPDF, KGhostView, KFax, KFaxview, and KDVI in KDE 4.
- Supported Formats: PDF, PS, Tiff, CHM, DjVu, Images, DVI, XPS, Fiction Book, Comic Book, Plucker, EPub, Fax
- Sidebar with contents, thumbnails, reviews, and bookmarks
- Annotations support
In the following tutorial, you will learn to install the Okular on Ubuntu 22.04 LTS Jammy Jellyfish using three methods: apt package manager, flatpak package manager, and snapcraft package manager, with some tips for maintaining or removing Okular in the future.
Table of Contents
Before you begin, make sure your system is up-to-date to avoid any conflicts during the installation, and for good practice, use the terminal command as follows.
sudo apt update && sudo apt upgrade -y
Install Okular – APT Method
The first option is to use the Ubuntu 22.04 default APT repository. This is a stable and secure version and is most recommended to install over any other package manager but can be outdated compared to Flatpaks alternative option that is usually up-to-date.
First, execute the following apt install command.
sudo apt install okular -y
The following two methods provide newer Okular packages, especially as Ubuntu 22.04 LTS ages.
Install Okular – Snapcraft Method
The second option is to install with Snap. The Snapcraft package manager should be installed on your Ubuntu desktop unless you have removed it previously.
Note that Flatpak has faster releases of Okular than Snapcraft.
For users that removed snapd, re-run the following command:
sudo apt install snapd -y
Once installed, you will need to restart your system, or else the icons may not appear; if you skip a repeat and notice any issues, reboot.
Snap installed? Skip the following few lines and proceed straight to the installation with Snap
Next, some packages come in classic, so you need to create a symlink to enable classic snap support, so it is best to run this command for the best snap compatibility.
sudo ln -s /var/lib/snapd/snap /snap
Install the core files to avoid conflicting issues.
sudo snap install core
Next, enter the following snap command to install.
sudo snap install okular
Install Okular – Flatpak Method
The third option is to use the Flatpak package manager. This comes installed on Ubuntu unless you removed it. This is another popular option similar to Snap but is featured amongst many distributions as an alternative third-party installation package manager for the latest packages.
First, re-install Flatpak if you have removed the package manager previously.
sudo apt install flatpak -y
Next, you need to enable Flatpack using the following command in your terminal:
sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
Ideally, you should reboot at this stage; if you skip this and notice icons not appearing, the reboot will generate the paths required for the future.
Now run the installation using the following flatpak command.
flatpak install flathub org.kde.okular -y
How to Launch Okular
Now that you have the software installed, launching can be done in a few ways.
First, you can launch the application immediately by typing the following command in your terminal.
If you would like to launch Okular and continue using the terminal, use the <application-name> & command.
Snap users need to use the snap run <application> command.
sudo snap run okular
Lastly, Flatpak users can run from the terminal using the following command.
flatpak run org.kde.okular
However, this isn’t practical, and you would use the following path on your desktop to open it.
Activities (top-right corner) > Show Applications > Okular
Once you open Okular, you will see the first default landing screen, where you can begin to use the document viewer. The settings menu has a few configuration operations to customize the look and operation compared to the bare-bones default viewer window.
How to Update/Upgrade Okular
Updates should appear in notifications, but if these fail to show sometimes, it is recommended to check using the terminal regardless use one of the following commands to check for updates.
sudo apt update
sudo snap refresh
How to Remove (Uninstall) Okular
Use one of the following commands to suit the original installation method for users who no longer require the application.
APT Remove Method
sudo apt autoremove okular --purge -y
Note that autoremove will also delete any unused packages from Okular and any other leftovers from previous applications. Most times, this is safe to do and should be done to keep your system from being bloated.
Flatpak Remove Method
flatpak remove --delete-data org.kde.okular -y
Next, run the following command for any leftover clean-ups required, similar to the autoremove command described for the apt remove example command.
flatpak remove --unused
Snapcraft Remove Method
sudo snap remove okular
Comments and Conclusion
In the tutorial, you have learned how to install Okular on Ubuntu 22.04 LTS Jammy Jellyfish using one of the three installation methods.
If you are looking for a versatile and powerful document viewer who can work on multiple platforms, Okular is excellent. It has all the features you need to view your documents easily, and the KDE community is constantly improving it. Give it a try today!