PDF Studio Viewer 6. PDF Viewer and reader can be installed in different ways depending on your needs. There is a variety of different readers available for Linux. Most of the popular PDF Viewer are available on AUR (Image) or as part of the Fedora/Ubuntu/RHEL/CentOS repositories. Open source alternative (GPLv3) is available through AUR and available for Fedora/Mint/open SUSE It is an app that is based on the Adobe Reader/Adobe Acrobat Reader and can view your PDF files, to convert your PDF into the PDF/TXT file. PDF Viewer allows you to view documents online without requiring the need to install any plugin for your web browser. In case of non-free PDF file conversion (such as converting PDF to a .TXT file) it will be free, so don't worry. 7. MuPDF PDF Viewer is a multi-platform, fast PDF reader for all popular browsers. It supports PDF, DOC, Doc, XLS, ZIP, PSD, AI, TXT, FEE, TAR, HTML5, PUB, CBZ, MOB and Kindle formats. The viewer can be downloaded on both Ubuntu and Linux Mint. Download it by using the following commands in a terminal or command line shell.