Archives For Howtos

Calibre, cross-platform open-source comprehensive e-book software, released version 5.0 with some great new features.

Calibre 5.0 features highlighting in the E-book viewer. Simply select text and click the Highlight selection button. It can be colors, underlines, strikethrough, etc. and has added notes. All highlights can be both stored in EPUB files and centrally in the Calibre library.

The new release also feature Dark mode support. On Windows and Mac, it is activated automatically based on OS settings. In Ubuntu Linux, launch the software in dark mode via CALIBRE_USE_DARK_PALETTE=1 environment variable.
Other features in the release include:

  • Python 3 port. Some third-party plugins will no longer work, until they are also ported to Python 3.
  • Support both vertical and right-to-left text.
  • Enhanced search in the E-book viewer
  • Support bookmarking in content server’s in-browser viewer

How to Install Calibre 5.0 in Ubuntu Linux:

Open terminal (Ctrl+Alt+T) and run command to download & install the official installer script:

sudo -v && wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sudo sh /dev/stdin

Once installed, open it from system application launcher and enjoy!

Enable Calibre Dark Mode in Ubuntu:

To temporarily open the e-book reader in dark mode, simply run command:

export CALIBRE_USE_DARK_PALETTE=1 && calibre

To make it permanent, run command to edit the .desktop file and do:

  • add env CALIBRE_USE_DARK_PALETTE=1 at the beginning of the values of “TryExec” and “Exec”.
  • remove --detach flag, or the shortcut icon will disappear.

How to Remove Calibre E-book software in Linux:

To remove the software, open terminal and run command:

sudo calibre-uninstall

For those prefer Deb package to the containerized Snap or Flatpak package, Emacs text editor 27.1 now is available to install via an Ubuntu PPA for all the current releases.

GNU Emacs 27.1 was released more than 1 month ago. Thanks to Kevin Kelley, you can now install it in Ubuntu via this PPA repository.

The PPA package features:

  • native support for JSON
  • support for ACLs
  • support for libgmp
  • support for enhanced text rendering through Cairo and HarfBuzz
  • remove ImageMagick support
  • remove xwidgets support for Ubuntu 16.04.

1. Open terminal either from system application launcher or by pressing Ctrl+Alt+T on keyboard. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:kelleyk/emacs

Type user password (no asterisk feedback) if it asks and hit Enter to continue.

2. Then refresh system package cache and install the editor via 2 commands:

sudo apt update

sudo apt install emacs27

If you want, you can install the text-only user interface via sudo apt install emacs27-nox.

The PPA also contains emacs26 and emacs25 packages for choices.

(Optional) To uninstall the PPA, either go to ‘Software & Updater -> Other Software’, or run command:

sudo add-apt-repository --remove ppa:kelleyk/emacs

And remove the Emacs text editor if you want by running command:

sudo apt remove --autoremove emacs27

Visual Studio Code IDE

Visual Studio Code IDE 1.49 was released a few days ago. Here’s how to install it in Ubuntu 20.04, Ubuntu 18.04.

Visual Studio Code 1.49 release highlights include:

  • Format modified text – Limit formatting to just the code you’ve changed.
  • Add support for changing text casing during global Search and Replace.
  • Display pending changes per repository in the Source Control repositories view
  • Debug Console now supports quickly filter and find debugging output.
  • Improved JS debugger Auto Attach – “Smart” Auto Attach to Node.js scripts or test runners.
  • TypeScript optional chaining refactoring – Convert multiple checks to a concise optional chain.
  • JSDoc @deprecated tag support – IntelliSense clearly shows APIs marked as deprecated.
  • Notebook UX updates – Cell Status bar contributions, enhanced notebook diff editor.

How to Install VS Code 1.49 in Ubuntu:

The official .deb package is available to download at the link below:

Download VS Code (.deb)

Grab the deb and install it via either Gdebi package manager or command in terminal (Ctrl+Alt+T):

sudo dpkg -i ~/Downloads/code_*.deb; sudo apt -f install

For those who want to receive updates for VS Code via Software Updater utility, add the Microsoft repository via following steps (64bit only):

1. Open terminal (Ctrl+Alt+T) and run command to add the repository:

sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/vscode stable main" > /etc/apt/sources.list.d/vscode.list'

2. Download and install the repository key via commands:

curl https://packages.microsoft.com/keys/microsoft.asc | gpg --dearmor > microsoft.gpg

sudo mv microsoft.gpg /etc/apt/trusted.gpg.d/microsoft.gpg

3. Finally install the IDE via command:

sudo apt-get install code

Uninstall Visual Studio Code:

To remove the code editor, either use Synaptic Package Manager or run command:

sudo apt-get remove --autoremove code

And remove the Microsoft repository by launching Software & Updates utility and navigating to Other Software tab.

Oracle Java 15 was released a few days ago. The installer script has been made into PPA for Ubuntu 16.04, Ubuntu 18.04, Ubuntu 20.04, and their derivatives.

See the release note for what’s new in Oracle Java 15.

The “Linux Uprising” team ppa has made the installer script, which automatically downloads and installs Oracle JDK 15 package, and sets Java 15 as the default Java version (setting JAVA_HOME, etc.) on 64-bit Ubuntu based system.

1.) Open terminal and run command to add the PPA:

sudo add-apt-repository ppa:linuxuprising/java

Type user password (no asterisk feedback) when it asks and hit Enter to continue.

2.) After adding PPA, refresh system package cache and install the script:

sudo apt update

sudo apt install oracle-java15-installer

Once the package is installed, you have to accept the license (press Tab to highlight) before starting the download process.

And after installed Oracle Java 15, check via java --version command:

(Optional) To uninstall the PPA repository, run command in terminal:

sudo add-apt-repository --remove ppa:linuxuprising/java

And remove Oracle Java 15 if you want by running command:

sudo apt-get remove oracle-java15-installer

Want to change CPU frequency scaling in Ubuntu 20.04? There’s a gnome shell extension can do the job.

CPU Power Manager is a Gnome-Shell extension for intel-pstate driver. If you have an Intel Core i CPU, the extension will offer an indicator menu for changing CPU frequency scaling.

To install the extension, simply do following steps one by one:

1.) Open terminal and install chrome-gnome-shell package if you’re first time installing a Gnome shell extension:

sudo apt install chrome-gnome-shell

2. Go to extension page in your web browser. If you don’t see the toggle icon, click link to install browser extension:

3. Finally refresh the web page (see the link in step 2), toggle on and install the extension.

Once installed, you’ll see the indicator applet in system tray area. To make it work, you have to click “Attempt installation” option, type user password and hit Enter.

(Optional) To remove this gnome shell extension, either go to link in step 2 and turn it off, or use Extensions tool.