News, Tutorials, Howtos for Ubuntu Linux
Looking for an app to sign, annotate, or edit PDF files in Ubuntu Linux? Here I’m going to introduce some for you!
PDF, stands for Portable Document Format, is a file format that’s popular for office use. Besides using Adobe Acrobat, Linux has quite a few applications that can edit this file format.
OnlyOffice, the popular free open-source office suite, announced new 8.1 release for its desktop editors.
The Desktop Editors is the offline use version of OnlyOffice office suite. It’s made up of Document, Spreadsheet, Presentation, and PDF Form apps, and, supports collaborative editing by connecting to a cloud service.
The new 8.1 release finally added full-featured PDF editing support for the both online and offline apps. After opened a PDF file, go to Home -> Edit PDF to toggle between viewing and editing mode.
When in editing PDF mode, you’ll see the tool-bar options to edit text, add, rotate and delete pages, insert various objects, such as text boxes, shapes, images, hyperlinks, tables, and more.
This simple tutorial shows how to install Adobe Acrobat Reader 9.5.5 in Ubuntu 24.04, Ubuntu 22.04, Ubuntu 20.04, and most other Linux.
Adobe has discontinued Linux support for its Acrobat PDF reader for many years! There are now many free open-source Linux apps for reading and/or editing PDF files.
However, if you like, the old Adobe Acrobat Reader 9.5.5 is still can be installed in current Ubuntu and other Linux, though it’s unmaintained and may contain security vulnerabilities.
NOTE: Adobe Reader 9.5.5 discontinued in 2013, it may have bugs and security issues! Install and use it at your own risk!
Thanks to @Ray Schumacher (see the comment below), Adobe website still provide native .deb package for the v9.5.5 version. It did install in my case in Ubuntu 24.04, however refused to launch due to the error below:
/opt/Adobe/Reader9/Reader/intellinux/bin/acroread: error while loading shared libraries: libgdk_pixbuf_xlib-2.0.so.0: cannot open shared object file: No such file or directory
The libgdk-pixbuf-2.0-0:i386 package offers the missing library, but it somehow refused to install in my test. So, this tutorial shows you how to install the Flatpak package instead, which works in all current Ubuntu releases, Fedora, Debian, Arch, and most other Linux.
Flatpak is an universal Linux package format that runs in sandbox environment. It takes more disk space due to shared run-time libraries, however can be more safe since it runs in container.
Ubuntu does NOT support Flatpak out-of-the-box, due to favor of Snap. It’s however easy to add it support by doing the steps below one by one.
1. (Ubuntu 16.04|18.04 only) For the old Ubuntu 16.04 and Ubuntu 18.04, press Ctrl+Alt+T on keyboard to open terminal. And, run command to add the Flatpak official PPA.
sudo add-apt-repository ppa:flatpak/stable
Then, update system package cache via:
sudo apt update
2. Press Ctrl+Alt+T on keyboard to open terminal. When terminal opens, run command to enable Flatpak support:
sudo apt install flatpak
For other Linux, follow this official setup guide instead for Flatpak support.
Once you got the file format support, then run the command below to install the Flatpak app package:
flatpak install https://dl.flathub.org/repo/appstream/com.adobe.Reader.flatpakref
Flatpak runs in sandbox. Though, the PDF reader itself only takes 59 MB, it needs also download & install hundred of MB run-time libraries.
Once installed, either right-click on your PDF file and select “Open With Other Application” to choose Adobe Reader, or just search for and launch it from the overview screen.
NOTE: If this is the first app installed as Flatpak package in your system, you may need to log out and back in to make app icon visible.
As mentioned, the Flatpak package runs in sandbox environment, which has NO permission by default to access printing system.
To enable this feature, first, open terminal (Ctrl+Alt+T) and run command to install Flatseal app:
flatpak install https://dl.flathub.org/repo/appstream/com.github.tchx84.Flatseal.flatpakref
Then, launch the “Flatseal” app, navigate to “Adobe Reader” in left pane of the pop-up app window, finally scroll down in right, find-out and turn on the toggle option for “Printing system”.
NOTE: If you intent to use network printer, then you also need to enable “Network” toggle option for this app package.
To remove the software package, also open terminal (Ctrl+Alt+T) and run command:
flatpak uninstall --delete-data com.adobe.Reader
You may also run command to remove unused runtime libraries to free up disk space.
flatpak uninstall --unused
For those want to unlock / decrypt PDF files, there’s now a stupid simple graphical tool to do the job in Linux.
It’s easy to encrypt you PDF files in Ubuntu Linux since the built-in LibreOffice office suite has the option on ‘Export as PDF’ dialog. However, there seems no easy way to remove password for PDF file, other than using qpdf command:
qpdf --decrypt --password=<PASSWORD> input.pdf output.pdf
unlockR is a new GTK4 application that use Libadwaita to provide a modern simple user interface to decrypt your PDF files.
It’s so simple that you just need to click ‘Open a File‘ to select your PDF, then type the password, and finally hit ‘Decrypt’. It doesn’t change the original file, but generates a new PDF without password protect.
As the picture shows, it has both light and dark mode that switches automatically according your system color scheme.
NOTE: This app is NOT about to crack password on a PDF file. You need the password to be able to decrypt it.
It is a free open-software software works on both Linux and Windows. For Windows package, just grab the zip from github releases page:
For Linux, it offers the binary package via universal Flatpak. Ubuntu user need to first press Ctrl+Alt+T on keyboard to open terminal, and run command to install the Flatpak daemon:
sudo apt install flatpak
Next, install the app package via command:
flatpak install https://dl.flathub.org/repo/appstream/com.github.jkotra.unlockr.flatpakref
Like normal applications, search for and open it from ‘Activities’ overview (or start menu) after installation.
To remove the Flatpak package, open terminal and run command:
flatpak uninstall --delete-data com.github.jkotra.unlockr
You may also clear useless runtime libraries via flatpak uninstall --unused.
Working with PDF files regularly in Ubuntu Linux? QPDF Tools is a nifty tool to manage your PDF documents.
It’s a free and open-source software, easy to use Qt based user interface for Ghostscript and Stapler, with ability to compress, split, merge and rotate your pdf documents.
The main window is simple and works with 4 buttons. Click the action you want to do for the PDF documents. Then select the PDF along with a few options and click the button to go.
The Compress a PDF file option will change the resolution for printing, Ebooks, or screen optimized. It also reduce the file size depends on the option you choose.
It however may stuck a few seconds when you clicking ‘Save‘ button on exporting file dialog.
While ‘Merge PDF files‘ option allows to add multiple PDF files, arrange them, and convert them into single, the ‘Spile a PDF file‘ option allows to extract all PDF pages or export from one page to another. And ‘Rotate a PDF file‘ can rotate left or right with live preview.
The DEB package for Ubuntu, Debian, Linux Mint, as well as the source tarball are available to download at the link below:
The software developer also maintains an Ubuntu PPA that support all current releases, e.g., Ubuntu 18.04, Ubuntu 20.04, Ubuntu 20.10, and Ubuntu 21.04. The packages for old releases, e.g., Ubuntu 12.04, Ubuntu 14.04, and Ubuntu 16.04 are also available.
1.) Open terminal from system app launcher. When it opens, run command to add the PPA:
sudo add-apt-repository ppa:silash35/qpdftools
2.) Then refresh package cache (optional for Ubuntu 20.04 & higher) and install the tool via commands:
sudo apt update
sudo apt install qpdftools
Once installed, open the tool from your system application launcher and enjoy!
While the Ubuntu PPA is used to install or upgrade the software package, you can safely remove it either by running command in terminal:
sudo add-apt-repository --remove ppa:silash35/qpdftools
Or by going to ‘Software & Updates’ -> ‘Other Software’, and remove the relevant line.
To remove the software, either use Synaptic Package Manager or run command:
sudo apt remove --purge qpdftools
