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What CoolReader is and which formats it supports
CoolReader is an XML/CSS-based ebook reader for Linux. Debian package metadata describes it as fast and small, and lists support for FB2, FB3, TXT, RTF, DOC, DOCX, ODT, TCR, HTML, EPUB, CHM, PDB and MOBI. Format support does not guarantee that every file will render identically; layout can depend on the document and its styling.
Check whether the CoolReader PPA supports your release
The PPA used in older instructions is ppa:vovansrnd/coolreader. Its indexed package path is for Ubuntu precise, an obsolete Ubuntu series. That historical listing is not evidence that the PPA currently publishes packages for your Ubuntu release or the Ubuntu base of your Linux Mint release.
Before running any commands, open the PPA’s current Launchpad overview and check that your release series is listed and that the cr3 package is published for it. Also verify the PPA owner and signing-key information. Do not infer current support merely because a PPA page still loads.
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- The lightest and most compact Kindle - Now with a brighter front light at max setting, higher contrast ratio, and faster page turns for an enhanced reading experience.
- Effortless reading in any light - Read comfortably with a 6“ glare-free display, adjustable front light—now 25% brighter at max setting—and dark mode.
- Escape into your books - Tune out messages, emails, and social media with a distraction-free reading experience.
- Read for a while - Get up to 6 weeks of battery life on a single charge.
- Take your library with you – 16 GB storage holds thousands of books.
Ubuntu cautions: “Only add software repositories from sources that you trust!” Ubuntu also warns that third-party repositories are not checked by Ubuntu members for security or reliability and may contain harmful software. Adding a PPA gives its packages a route into your system’s package manager, so proceed only if you trust the owner and understand the source.
Install CoolReader from the PPA
Use these commands only if the current PPA overview confirms a compatible series and a published cr3 package. The commands below are the historical sequence documented by an older installation guide; that guide identified the package as version 3.1.2-39, not as a current version.
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Add the PPA:
sudo add-apt-repository ppa:vovansrnd/coolreaderRank #2
Amazon Kindle Paperwhite 16GB (2024 model) – 7" glare-free display and weeks of battery life – Black- Our fastest Kindle Paperwhite ever – The next-generation 7“ Paperwhite display has a higher contrast ratio and 25% faster page turns.
- Ready for travel – The ultra-thin design has a larger glare-free screen so pages stay sharp no matter where you are.
- Escape into your books – Your Kindle doesn’t have social media, notifications, or other distracting apps.
- Battery life for your longest novel – A single charge via USB-C lasts up to 12 weeks.
- Read in any light – Adjust the display from white to amber to read in bright sunlight or in the dark.
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Refresh apt’s package index:
sudo apt-get update -
Install the package:
sudo apt-get install cr3
When prompted while adding the PPA, review the repository information before confirming. The first command adds a source under /etc/apt/sources.list.d; the update command retrieves package metadata, and the install command asks apt to install cr3 and manage its dependencies. Ubuntu documents the equivalent modern install form as sudo apt install cr3.
Troubleshoot “PPA does not support this Ubuntu version” or “no release file”
If adding the PPA reports that the distribution is unsupported or that no release file exists, apt cannot use that repository for the configured release. If apt-get install cr3 reports that the package cannot be located, the package index does not contain an installable cr3 package from the enabled sources. Do not change your system’s reported Ubuntu codename to force an old repository to apply; use the project’s source-build instructions instead.
On Linux Mint, the relevant series is the Ubuntu base release used by your Mint version, not simply the Mint version name. Confirm that base series against the PPA’s published series before enabling it. If the PPA does not list it, treat the PPA route as unsupported for that installation.
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- Our fastest Kindle Paperwhite ever – The next-generation 7“ Paperwhite display has a higher contrast ratio and 25% faster page turns.
- Upgrade your reading experience – The Signature Edition features an auto-adjusting front light, wireless charging, and 32 GB storage.
- Ready for travel – The ultra-thin design has a larger glare-free screen so pages stay sharp no matter where you are.
- Escape into your books – Your Kindle doesn’t have social media, notifications, or other distracting apps.
- Adapts to your surroundings – The auto-adjusting front light lets you read in the brightest sunlight or late into the night.
Build CoolReader from source if the PPA is unavailable
The CoolReader project documents a CMake source build for Ubuntu. The repository lists these build dependencies: build-essential, cmake, zlib1g-dev, libpng-dev, libjpeg-dev, libfreetype6-dev, libfontconfig1-dev, libharfbuzz-dev, libfribidi-dev, libunibreak-dev, libzstd-dev and libutf8proc-dev. For the Qt5 frontend, it additionally lists qtbase5-dev and qttools5-dev.
Follow the project’s build instructions for the actual CMake configuration and build commands; the dependency list alone is not a complete build procedure. Check those instructions against your Ubuntu or Mint base release, since available package names and versions can differ.
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PPA installation or source build?
| Consideration | PPA | Source build |
|---|---|---|
| Effort | Shorter when the PPA publishes a compatible package: add the repository, refresh apt, and install cr3. |
More work: install build dependencies and follow the project’s CMake instructions. |
| Release support | Depends on the PPA publishing a package for the system’s Ubuntu series; current support is not established here. | The project documents an Ubuntu build route, but you must check its instructions for your release. |
| Trust and provenance | Requires trusting the PPA owner and checking its signing and package details. | Uses the project’s source-build instructions; obtain the source from the project and follow its documented process. |
| Dependencies | Apt handles dependencies declared by the package. | You install the listed development dependencies and compile the application. |
| Removal and rollback | Apt manages the installed package, but removing the PPA and managing packages already installed from it are separate considerations. | Removal depends on the project’s build/install procedure; the cited dependency list does not establish an uninstall command. |
| Package freshness | Depends on what version the PPA currently publishes; the historical guide’s 3.1.2-39 label is not a current-version guarantee. | Depends on the source version you obtain and the project’s build instructions. |
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
