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☐ ☆ ✇ UbuntuHandbook

This GTK App Checks Contrast Ratio Between 2 Colors in Ubuntu Linux

By: Ji m

Designers and website developers may sometimes need to check WCAG color contrast to make web content more accessible to people with disabilities.

Without using an online website each time, Linux has a stylish GTK4 app “Contrast” which allows to check whether the contrast between two colors meet the WCAG requirements.

The app has a simple user interface that displays one color as background and another as font color of the text. By clicking on the double arrow icon between two color codes, it reverses background color as text font and font color as background.

User may select color either by clicking on the circle icon before hex code (e.g., #F3F6F9), or by using the color picker tool after the code.

Contrast Select Color

The app will display color contrast result with text, such as “Awesome, Pretty Good, Not Bad, and Nope, along with short description tells whether the color combination will properly work.

It also displays a score bar tells that if the color contrast meets the 3 WCAG Levels: A, AA and AAA. And, a contrast ratio is displayed at the bottom.

Reversed colors

How to Install Contrast in Ubuntu Linux:

As a GTK4 app, Contrast so far only available to install as Flatpak which runs in sandbox.

1. Firstly, press Ctrl+Alt+T on keyboard and open terminal. When it opens, run command to install the Flatpak daemon:

sudo apt install flatpak

For Ubuntu 18.04 and Ubuntu 16.04, the flatpak PPA is required to get the package.

2. Next, run command to install the WCAG color contrast app:

flatpak install

Note: If you’re first time installing a Gnome app as Flatpak, it will install the required GNOME 41 platform as shared runtime libraries, which take hundreds of megabytes disk space.

Once installed, search for and open the app from activities overview screen.

How to Remove Contrast Flatpak app:

To remove the software package, press Ctrl+Alt+T and run command in terminal:

flatpak uninstall --delete-data

And use flatpak uninstall --unused command may remove useless run-times if any.

☐ ☆ ✇ UbuntuHandbook

Deepin 20.3 Released with Kernel 5.15, Scrolling Screenshot Support

By: Ji m

The beautiful Debian based Linux distribution Deepin 20.3 was released. Features Kernel 5.15, new features and optimizations for its core apps.

The stable Linux kernel has been updated to v5.15 with better support for Intel 12th Gen processors and NTFS file systems. Though the iso image by default boots with 5.10 LTS kernel, user have to select the new kernel to install from ‘Advanced’ menu in Grub boot-loader.

The Deepin screen capture can now take scrolling screenshots via the ‘Scrollshot‘ option. After selecting an app window to capture, a ‘Scrollshot’ option is available in tool-bar. By clicking on it, you may scroll the page to take a continuous screenshot with real-time preview. Also OCR is supported in this mode to extract text from image.

Deepin Scrollshot

In the extended mode, you may now set how to display the Dock on multiple displays via its right-click context menu.

Other changes in Deepin 20.3 include:

  • Video search, preview, and management in the Album app.
  • Add support for 2K hard decoding of OLAND chips.
  • Add shortcut for Global Search, which also supports searching markdown files.
  • Add the print entrance in Document Viewer.
  • Improve the file manager, movie, music, as well as other core apps.

Get Deepin 20.3

Compare to other Linux, Deepin somehow requires too much disk space now: 64 GB at least and 128 GB recommended. And it does not provide a live system to try out before installing into disk.

To get it, go to the link button above. And see the release note at this page.

☐ ☆ ✇ UbuntuHandbook

GNOME Painting App Pinta 1.7.1 Released with Some New Features

By: Ji m

Free and open-source clone of Paint.Net 3.0, Pinta, released version 1.7.1 a few days ago with improvements and bug-fixes.

The release is the final version based on GTK2, as the GTK3 / .NET 6 version is nearly ready!

Pinta 1.7.1 is a small release with minor new features to improve user experience. For image with large resolution (or zoomed in), you may use mouse wheel to scroll up / down. Now by holding Shift + mouse wheel, the canvas can be scrolled horizontally.

Same to GIMP, user may now press X to exchange background and foreground palette colors quickly in Pinta since v1.7.1. And, zooming in and out can now be done without pressing the Ctrl key

The release also improved the pop-up dialog when you trying to open an unsupported file format. The file open dialog by default shows only supported images, including ani, png, bmp, jpg, gif, icns, ico, jpeg, ora, pnm, qtif, svg, tga, tif, tiff, xbm, xpm. If you chose show “All files” and selected an unsupported file, it will prompt that file not support and show you all supported file formats.

Error when opening unsupported file and display all supported formats

Other changes in Pinta 1.7.1 include:

  • Use arrow keys to move per pixel in Move Selected Pixels and Move Selection tools
  • Use Shift to constrain to a uniform scale when scaling using Move Selected Pixels tool
  • Text in ‘About’ is selectable to copy version for use to report bugs.
  • Improve handling of memory allocation failures for large images
  • And various bug-fixes.

How to Install Pinta 1.7.1 in Ubuntu Linux:

Option 1: Install Pinta via Snap:

The app is easy to install in Ubuntu using the Snap package, by simply searching for and installing from Ubuntu Software (Snap Store):

Pinta Snap app in Ubuntu Software.

Option 2: Install Pinta via Ubuntu PPA:

NOTE: the PPA package crashes randomly due to outdated Mono library in Ubuntu. It’s highly to upgrade mono library if you want to install Pinta in native deb package.

The app has an official Ubuntu ppa that contains the latest packages for Ubuntu 18.04, Ubuntu 20.04, Ubuntu 21.04, and Ubuntu 21.10 so far.

Firstly, press Ctrl+Alt+T on keyboard to open terminal. Then run command to add the PPA:

sudo add-apt-repository ppa:pinta-maintainers/pinta-stable

Secondly, run command to update system cache if you’re still running Ubuntu 18.04:

sudo apt update

Finally, install Pinta via command:

sudo apt install pinta

Or, upgrade the app if an old version present in your system using Software Updater:

In addition, Pinta is also available to install as Flatpak package. Check in Flathub if you’re interested in it.

How to Remove Pinta from Ubuntu:

To remove Pinta installed via PPA package, run command in terminal (Ctrl+Alt+T):

sudo apt remove --autoremove pinta

And remove the PPA either via ‘Software & Updates‘ utility under Other Software tab, or by running command:

sudo add-apt-repository --remove ppa:pinta-maintainers/pinta-stable

For Pinta snap package, remove it either via Ubuntu Software or by using command:

snap remove --purge pinta
☐ ☆ ✇ UbuntuHandbook

Flatseal – Modern GNOME App to Change Flatpak App Permissions in Linux

By: Ji m

More and more apps today publish Linux packages as Flatpak. Though the run-time libraries take hundreds of megabytes disk space, some apps are really good and useful.

If you have some apps installed as Flatpak in Ubuntu or other Linux like me, then Flatseal may be useful to protect your privacy by managing permissions in per app basis.

Flatseal is a stylish GNOME app that displays all the installed Flatpak apps in the left pane. By selecting an app, it displays the basic information as well as permissions with toggle buttons. The app has an adaptive UI that works great on small screen size, e.g., Linux Phone.

With Flatseal, you may configure following permissions for your Flatpak apps:

  • Network access.
  • Sound server access.
  • GPU acceleration to reduce CPU usage.
  • System file or user file access.
  • Send notifications.
  • System bus and session bus.
  • Print system, smart card, webcam, bluetooth access, and more.

Note: some options (e.g., inter-process communications and X11/Wayland windowing system) may be required for the app to work. Switching those options off may cause function issues, though you may reset them easily afterwards.

As some options are not easy to understand, you may press F1 on keyboard to bring up the ‘help‘ window, which contains the descriptions for each toggle option. And, if permissions are removed and somehow no longer possible to reset, run command below (press Ctrl+Alt+T in Ubuntu to open terminal) to clear the changes and restart Flatseal.

rm ~/.local/share/flatpak/overrides/com.github.tchx84.Flatseal

How to install Flatseal in Ubuntu Linux:

The app itself is available to install as Flatpak package. To try it out, you must have already installed some apps as Flatpak. If not, you need to install the daemon first. For Ubuntu/Debian based systems, simply open terminal and run command:

sudo apt install flatpak

Next, install the Flatseal by running command in terminal:

flatpak install

Or use the command below if you already added the Flathub repository:

flatpak install flathub com.github.tchx84.Flatseal

As you see in picture, the app itself is about 683 KB, while run-time libraries take more than 700 MB. The run-times (e.g., GNOME platform) are shared libraries though that can be used for other Flatpak apps.

Uninstall Flatseal:

To remove the app, simply run command in terminal:

flatpak uninstall --delete-data com.github.tchx84.Flatseal

Note: removing Flatseal won’t reset the permission changes you made for the flatpak apps. You have to manually clear the config files under “~/.local/share/flatpak/overrides” directory to restore them.

☐ ☆ ✇ UbuntuHandbook

Modern Free Markdown Editor Ghostwriter 2.1.0 Released with New Features

By: Ji m

Ghostwriter, free and open-source markdown text editor, released version 2.1.0 with some new features. Here’s what’s new and how to install in Ubuntu.

Ghostwriter is a cross-platform, aesthetic and distraction-free Markdown editor works on Linux, Windows, and MacOS. It comes with live HTML preview, dark and light mode, focus mode, hemingway mode, autosave, MathJax, and built-in Cheat Sheet in the sidebar (toggle via F1) in case you forgot some Markdown syntax.

By releasing v2.1.0, it now auto-saves untitled documents to a draft folder, and provides a button in ‘Preferences’ to open that folder (it’s user Documents folder in my case).

And, it loads the last opened file on startup while providing an option to toggle on/off this feature. The bottom status bar can now display a different statistic. By clicking on it, you may choose to display how many words, characters, pages, sentences, paragraphs, or read time, write time, wpm, etc.

How to Install The Latest Ghostwriter 2.1.0 in Ubuntu:

The text editor has an official PPA that so far supports for Ubuntu 20.04 and Ubuntu 21.04. The Ubuntu 21.10 package is somehow not updated at the moment, you may check the link page though.

1.) Add the PPA:

Press Ctrl+Alt+T to open terminal. When it opens, run the command below to add the PPA repository:

sudo add-apt-repository ppa:wereturtle/ppa

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

2.) Refresh system package cache by running command in terminal. This is done automatically in Ubuntu 20.04 & higher while adding PPA, but some Ubuntu based systems may not.

sudo apt update

3.) Finally install ghostwriter via command:

sudo apt install ghostwriter

The software team also maintains Copr repository for Fedora 33/34/35 and rawhide users. Simply open terminal and run commands below one by one will install it in Fedora:

sudo dnf copr enable wereturtle/stable
sudo dnf install ghostwriter

Uninstall Ghostwriter:

To remove the markdown editor, open terminal and run command:

sudo apt remove --autoremove ghostwriter

And remove the Ubuntu PPA using “Software & Updates” utility under Other Software tab:

☐ ☆ ✇ UbuntuHandbook

KGX – Minimal Terminal Emulator Aims to be Core App for GNOME & Phosh

By: Ji m

KGX is a simple and user-friendly terminal emulator for GNOME. It aims to be a “Core” app for GNOME and Phosh, graphical shell for mobile devices like Purism’s Librem 5.

Rather than replacing GNOME Terminal, it’s on target to serve casual Linux user who rarely needs a terminal to carry out simple command line tasks. Via libhandy library, the terminal adjusts nicely to small screen sizes and for touch usage.

KGX terminal emulator. Image from

The name KGX is the station code for King’s Cross, the London terminus of the East Coast Main Line. The app is available in Ubuntu repositories since Ubuntu 21.04, though the package version is lag behind.

The stock KGX in Ubuntu 21.10 has a semi-transparent app window and the UI looks kinda like Gnome terminal. Though it’s lightweight and has less features.

KGX in Ubuntu 21.10

Install KGX in Ubuntu 21.10 / 22.04:

For Ubuntu 21.04, Ubuntu 21.10 and next Ubuntu 22.04, it’s easy to try out this terminal emulator by pressing Ctrl+Alt+T on keyboard, and then run command in terminal to install it:

sudo apt install kgx

Then, search for and open the terminal emulator from activities overview.

While the stock package is always old, you may build it from source which is available at KGX project page.

☐ ☆ ✇ UbuntuHandbook

Ubuntu PPA for Annotator – Elementary OS Image Annotation Tool

By: Ji m

Linux has quite a few image annotation tools. “Annotator” is the one designed for Elementary OS with specific features. Here’s how to install it in Ubuntu 20.04, Ubuntu 21.10, Ubuntu 22.04 via PPA.

Without using GIMP image editor, I sometimes uses Shutter to annotate image quickly. As well, Ksnip has some useful tools (e.g., drop shadow, invert color and add border) that I use regularly.

Annotator is an app looks kinda like MacOS Preview. Like other tools, it allows to add text, rectangle, ellipse, sequence number, line, arrow, blur effect, crop and resize image. What makes it different is the “Magnifier” tool. It adds a circle on your image and enlarge the area inside. By right-clicking on the circle, it offers option to change magnification.

Also, it allows to add stickers, such as industry, mobile and data icons, different type of arrows.

Install Annotator in Ubuntu:

Though the app is designed for Elementary OS, it works on other desktop environments. The developer team provides official package as Flatpak. Make sure the flatpak daemon is installed, you may then install the app via command:

flatpak install

However, the Flatpak package requires separated Elementary OS platform and SDK as run-time libraries. The run-times take about 700 MB space while the app itself is only a few hundred KB.

So I created this unofficial Ubuntu PPA for those want to try out this annotation tool with native DEB package. So far, Ubuntu 20.04, Ubuntu 21.04, Ubuntu 21.10, and Ubuntu 22.04 are supported.

1. Add the PPA

Press Ctrl+Alt+T on keyboard to open terminal. When it opens, run commands to add the PPA:

sudo add-apt-repository ppa:ubuntuhandbook1/annotator

Type user password, no visual feedback, when it asks and hit Enter to continue.

2. Update package cache

Ubuntu 20.04 and higher refresh system package cache automatically while adding PPA, but some Ubuntu based systems may not. To do it manually, run command:

sudo apt update

3. Install Annotator:

Finally, install the app using command:

sudo apt install com.github.phase1geo.annotator

Once installed, search for and open it from start menu (activities overview) and enjoy!

Remove Annotator & Ubuntu PPA:

To remove the Ubuntu PPA, use command:

sudo add-apt-repository --remove ppa:ubuntuhandbook1/annotator

And remove the annotation tool via:

sudo apt remove --autoremove com.github.phase1geo.annotator
☐ ☆ ✇ UbuntuHandbook

This App Tells When the Next Rocket will Launch in Linux Desktop / Phone

By: Ji m

For spaceflight enthusiasts, there’s now a GTK4 app for Linux Desktop and Phone (e.g., PinePhone, Librem 5) to keep track of upcoming rocket launches.

It’s “Space Launch”, an open-source app gets data of the launches from The app displays the next upcoming launches with information about the company and/or manufacturer, such as Rocket Lab and SpaceX. The location, date and time, and count down for the rocket launches.

Dark mode is supported and it may show more launches as schedule.

The app is currently in alpha release. More features will be added later. And it’s compatible with Linux Phone using Phosh.

Install Space Launch in Linux:

This app is available to install via Flatpak package. You may follow the steps below one by one to setup flatpak daemon and install Space Launch.

1.) Press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to install the Flatpak daemon:

sudo apt install flatpak

The old Ubuntu 18.04 and Ubuntu 16.04 may also install the app, though need to add Flatpak PPA first.

2.) Next, add the Flathub repository that hosts the packages via command:

flatpak remote-add --if-not-exists flathub

3.) Finally, install the app using command:

flatpak install flathub org.emilien.SpaceLaunch

The app package itself is about 75KB. Though, if you’re first time installing Gnome App as Flatpak, it may also install the run-time libraries take up a few hundred MB disk space.

After installation, search for and open the app from ‘Activities’ overview screen and enjoy!

How to Remove Space Launch:

To remove the app, simply run command in terminal:

flatpak uninstall --delete-data org.emilien.SpaceLaunch

And you may clear unused run-time libraries via command:

flatpak uninstall --unused
☐ ☆ ✇ UbuntuHandbook

Toggle Panel Visibility & Custom GNOME Shell All-In-One via Extension

By: Ji m

How to hide top-bar, remove left dock and ‘Activities’, as well as toggle visibility of a few other Gnome Panel items are often asked questions. I used to use a few extensions to do the jobs until met ‘Just Perfection’.

Just Perfection includes a list of options to toggle visibility of GNOME UI Elements, customize panel size, padding, and change the behavior.

Its settings page starts with a portrait of an old man (Sorry for my poor cultural knowledge, I don’t know who is he).

An old man in Just Perfection settings

Just scroll down, and you’ll see the options to:

  • override Gnome Shell theme to create a minimal desktop.
  • Hide top-bar.
  • Hide top-bar in overview screen.
  • Remove top left “Activities” button.
  • Disable (the focused) app-menu, clock, system tray menu (Aggregate menu).
  • Remove search box, workspace picker, close button & caption of selected app in overview
  • Disable the dock launcher, on screen display (when changing volume/brightness via Fn key).
  • Disable hot corner watermark animation.
  • Turn on/off icons for top-bar items.
  • Remove panel arrow (little triangle behind app-menu and battery icon).
  • Toggle hot corner, app gesture, type to search.
  • Customize panel position (top or bottom), clock position, panel size and button padding, animation speed, etc.

How to Install Just Perfection Extension:

The extension so far supports Gnome from v3.36 to v41, so Ubuntu 20.04 and higher may install it via following steps:

1.) Firstly, press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to install required libraries:

sudo apt install chrome-gnome-shell gnome-shell-extension-prefs

2.) Next, go to the extension web page and turn on the toggle icon to install it:

If you don’t see the toggle icon, click the link in the top to install browser extension and refresh the web page.

(NOTE: the default Firefox in Ubuntu 21.10 is a Snap app that does not support for installing Gnome Extensions.)

After installation, search for and open ‘Gnome Extensions‘ app from Activities overview screen and click the setting wheel for the extension to customize GNOME UI:

☐ ☆ ✇ UbuntuHandbook

How to Type Unusual Characters and Symbols in Ubuntu GNOME

By: Ji m

For Ubuntu, Fedora, and other Linux with GNOME desktop, here’s how to type unusual characters (e.g., , ©, ™, ¼, , etc) using the standard QWERTY computer keyboard.

Without using a virtual keyboard, the standard physical keyboard supports for inserting alternate characters and symbols using the Compose key in Linux. Here’s how to enable and use the key in Ubuntu 18.04, Ubuntu 20.04, Ubuntu 21.10 & higher with default GNOME desktop.

Enable Compose key in GNOME:

1. Firstly, search for and install “Gnome Tweaks” configuration tool via Ubuntu Software.

For those familiar with Linux commands may also press Ctrl+Alt+T on keyboard to open terminal and run command to install the tool:

sudo apt install gnome-tweaks

2. Secondly, open ‘Activities’ overview screen, search for and open ‘GNOME Tweaks’:

3. When the configuration tool opens, do:

  • Go to “Keyboard & Mouse” in the left pane.
  • Click on ‘Disable‘ area in the right side after the Compose Key setting.
  • Turn on the toggle in pop-up dialog.
  • Finally choose a key to use as compose key.

Type unusual characters via Compose Key:

After enabled the functions, you may now press Compose key, then start typing the keys below one by one to insert a character. For example, type Compose key then ~ finally u will input ũ. No need to hold the compose key, though you have to hit the key combination in a short time period in Ubuntu 21.10. For Ubuntu 20.04, it even works 1 min after the compose key is pressed.

Common Compose Key combinations via Wikipedia. In first column, you may replace a with most uppercase and lowercase vowels:

Press For Press For Press For Press For
‘ + a á a + e æ < + < « – + L £
” + a ä A + E Æ > + > » ^ + 0
` + a à o + e œ / + / \ ^ + 1 ¹
~ + a ã O + E Œ / + C ^ + 2 ²
^ + a â d + h ð / + o ø ^ + 3 ³
c + a ǎ D + H Ð / + O Ø ^ + _ + a ª
< + s š o + o ° ? + ? ¿ ^ + _ + o º
o + a å o + x ¤ ‘ + < _ + 0
– + a ā o + c © ‘ + > _ + 1
, + a ą o + r ® , + c ç _ +2
b + a ă s + o § . + C Ç _ + 3
? + a s + s ß ” + < ~ + n ñ
. + a ȧ S + S ” + > | + c ¢
. + ^ · t + h þ ! + ! ¡ = + y ¥
– + D Đ T + H Þ – + – + – = + c
t + m ™ – + – + . 1 + 2 ½
x + x × – + : ÷ 1 + 4 ¼
. + . – + d đ 3 + 4 ¾
☐ ☆ ✇ UbuntuHandbook

How to Show Day of Week in Top bar of Ubuntu 20.04 /21.10

By: Ji m

Ubuntu by default displays only date and time in the center of top-bar. Users have to click on it to see which day is today in drop-down calendar.

To make life easier, you may configure the GNOME desktop to show the day of week in top-bar. And, here’s how.

Option 1: Single command to Display Weekday in Top bar:

For those familiar with Linux commands, press Ctrl+Alt+T on keyboard to open terminal. When it opens, copy and paste the command below and hit run:

gsettings set org.gnome.desktop.interface clock-show-weekday true

After that, it shows the weekday name in short (e.g., Sat and Sun) immediately.

Option 2: Toggle Weekday Display via Gnome Tweaks:

The must have GNOME configuration tool ‘Gnome Tweaks’ provides the toggle option for those hate Linux commands. If you don’t have it, search for and install via Ubuntu Software:

Next, press Super/Windows key to bring up activities overview screen. Then search for and launch Gnome Tweaks. Navigate to “Top Bar” from left pane, and then you’ll see the option to toggle “Weekday”.

As you may know, the advanced configuration tool “Dconf Editor” also provides a graphical option to toggle this function at “org/gnome/desktop/interface”, though the previous two methods is good enough to do the trick.

That’s all. A quick glance at screen top now tell you the day of week. Enjoy!

☐ ☆ ✇ UbuntuHandbook

Telegrand is a Modern GTK4 Telegram Client for GNOME in Development

By: Ji m

For Ubuntu, Fedora, and other Linux with GNOME desktop, a modern GTK4 Telegram app “Telegrand” is under development.

Telegrand is the free open-source client written in Rust programming language. By using libadwaita library, it has an adaptive user interface to fit all screen sized.

Telegrand – The GTK4 Telegram GNOME App (Image by Marcus Behrendt in

Though Telegram has official app for Linux, this new app is worth expecting for GNOME users. As an in-development project, it isn’t considered stable software yet. So far, it supports log in via phone number or using QR code.

Sadly, my Telegram account got banned after trying the app via Flatpak, though I do not use the service (Telegram is blocked in my Country and no friend around uses this messenger).

Telegrand includes the Telegram’s test credentials by default, which are very limited, but usable (especially for development). However, it’s known that Telegram sometimes decides to ban accounts that use such credentials (especially newer accounts).

Try Telegrand in Your Linux:

Arch Linux user may try out the app using the AUR package with provided API credentials via meson options.

For other Linux, the latest flatpak build with the test API credentials is available to download:

Then, extract the package and open the folder that contains the flatpak in terminal. Finally, run command to install it:

flatpak install telegrand.flatpak

You must have flatpak daemon installed via sudo apt install flatpak command first.

NOTE: As mentioned, the flatpak package includes the test credentials. Telegram may ban accounts that use such credentials (especially newer accounts).

And to remove the Flatpak, use command:

flatpak uninstall --delete-data com.github.melix99.telegrand.Devel

Read more in github

☐ ☆ ✇ UbuntuHandbook

This Extension Adds Your Text as Watermark in Ubuntu 21.10 GNOME

By: Ji m

Want to display some text on your desktop as watermark? This extension makes it possible in Ubuntu 21.10, or Fedora 34/35 with GNOME 40+.

As I know, only Fedora so far display system logo as watermark in the bottom right of its GNOME desktop, though it’s enabled only for the default wallpaper by default.

‘Activate Gnome’ is the extension, which adds semi-transparent text ‘Activate Gnome – Go to Settings to activate Gnome‘ in the bottom right corner of GNOME 40+ desktop.

GNOME with Watermark

The text displayed as two lines. Via Gnome Extensions app, user may change the text and move it to anywhere in the desktop using the extension settings dialog.

Change the Text to display, and watermark position

Though it’s useless but funny. And, instead of text only, maybe it should add logo image support.

Install “Activate Gnome” Extension:

1.) To install a Gnome Extension, you need to first make sure chrome-gnome-shell package is installed.

Press Ctrl+Alt+T on keyboard to open terminal and run command:

sudo apt install chrome-gnome-shell gnome-shell-extension-prefs

The command will also install the ‘Gnome Extensions App’ to manage extensions.

2.) Next, go to the link button below in your web browser. Turn on the slider to install the extension.

NOTE: The default Firefox in Ubuntu 21.10 is Snap app that does not support installing Gnome extensions. Use another browser or install Firefox as Deb via sudo apt install firefox command.

Turn on the slider to install extension

Don’t see the slider icon? Click the ‘click here to install browser extension‘ link in that page to install browser extension and REFRESH the page.

Once installed, search for and open ‘Gnome Extensions’ app from activities overview. And finally, input the text that you want to display (see picture 2).

That’s it. Enjoy!

☐ ☆ ✇ UbuntuHandbook

Linux Mint’s Sticky Note App Looks Great Now! Here’s how to get it in Ubuntu

By: Ji m

For those looking for Google Keep or Windows Sticky Notes style desktop noting app, Linux Mint’s “sticky” is a good choice for Ubuntu Linux.

Linux Mint maintains some great apps. Sticky is one of them that sticks an electronic version of Post-it Note on your desktop. It’s GTK3 app written in Python3 and works on most desktop environments.

With it, you may create as many notes as possible on desktop. And, it allows to set different color palette for each note: Blue, Green, Magenta, Orange, Purple, Red, Teal, and Yellow.

By right-clicking on header, it allows to set title for your note, and make it “Always on Top”. And, it supports format options including: Bold, Italic, Fixed Width, Underline, Strikethrough, Highlight, Header, toggle Checklist and Bullets. There are many other features, e.g., emoji, language, undo and redo support!

Linux Mint apps used to have right angles which are a little bit ugly in GNOME desktop. Now, it’s switching to rounded title-bar corners which looks native in Ubuntu, though it still lacks an indicator applet.

The app starts as group dialog with button in the bottom to add / remove notes, though each note itself has the new and delete buttons.

How to Install Linux Mint’s Sticky Notes in Ubuntu:

Besides adding Linux Mint repository and managing package priority, this unofficial PPA maintains useful Linux Mint apps, so far for Ubuntu 18.04, Ubuntu 20.04, Ubuntu 21.04, and Ubuntu 21.10.

1. Add Ubuntu PPA:

Press Ctrl+Alt+T on keyboard to open terminal, then run command to add the PPA:

sudo add-apt-repository ppa:kelebek333/mint-tools

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

2. Update package cache.

Next, refresh system package cache by running command below in terminal, though it’s done automatically since Ubuntu 20.04 while adding PPA.

sudo apt update

3. Install sticky:

Finally, install the sticky notes app via command:

sudo apt install sticky

Once installed, search for and open ‘Sticky’ from activities overview screen and enjoy!

How to remove Sticky Notes App:

To remove the app, open terminal (Ctrl+Alt+T) and run command:

sudo apt remove sticky --autoremove

And, remove the Ubuntu PPA either using “Software & Updates” app under “Other Software” tab or by running command:

sudo add-apt-repository --remove ppa:kelebek333/mint-tools
☐ ☆ ✇ UbuntuHandbook

[Workaround] Blurry / Pixelated Text Font in Ubuntu Software of Ubuntu 21.10

By: Ji m

The Ubuntu Software app in Ubuntu 21.10 Impish has an ugly font rendering on default Wayland. The text in the app looks a bit pixelated.

I found the issue firstly when Impish was in beta stage. The issue was reported to also affect LibreOffice, Chromium, and other Snap apps, though most of them has been updated with it fixed.

Ubuntu Software with Bad Font

According to Daniel van Vugt, this issue is caused by a few key settings change. The following keys has been removed in Ubuntu 21.10:

org.gnome.settings-daemon.plugins.xsettings antialiasing
org.gnome.settings-daemon.plugins.xsettings hinting
org.gnome.settings-daemon.plugins.xsettings rgba-order

And, following ones take the places instead:

org.gnome.desktop.interface font-antialiasing
org.gnome.desktop.interface font-hinting
org.gnome.desktop.interface font-rgba-order

Not only Snap apps, but also font-manager and Gnome Tweaks are affected by this change. And, Ubuntu Software (aka “Snap Store”) has fixed the issue in via the current beta release.

Snap Store Beta

Upgrade Snap Store via Beta Channel:

So the solution is either wait until Canonical published the update, or update Snap Store (Ubuntu Software) through beta channel if you use it regularly.

To do so, simply press Ctrl+Alt+T on keyboard to open terminal, and then run command:

snap refresh --channel beta snap-store

After that, font will be properly loaded next boot.

If you’ve found that Snap Store in stable channel has been updated to version higher than “3.38.0-66”. You may revert back by running command:

snap refresh --channel stable snap-store

That’s it. Enjoy!

☐ ☆ ✇ UbuntuHandbook

How to Set Time Limits for Your Kids in Ubuntu 20.04 / 21.10 & Debian 11

By: Ji m

This simple tutorial shows how to limit the time that your kids spend on PC running with Ubuntu or Debian.

GNOME, Ubuntu’s default desktop environment, is working on parental control app (Malcontent) though it so far lacks the time limitation feature. In this tutorial, I’m going to introduce Timekrp-nExT, a screen time managing app works on GNOME, XFCE, KDE, and all other Linux desktops.

1. Add A Standard Account for Kid:

Firstly, you need to create an account for your child with restricted permission. For Ubuntu and Debian with GNOME, it must be “standard” (non-administrator).

Open “Settings” and go to “Users” from left pane. Then click “Unlock” and type user password to authentication. After that, add a standard user for kid.

Create “standard” user for kid

2. Install Timekpr-nExT:

a.) Add its official PPA:

The software app is available in Ubuntu repositories since Ubuntu 20.10. For Ubuntu 16.04, Ubuntu 18.04 and Ubuntu 20.04, you have to press Ctrl+Alt+T to open terminal and run command to add its PPA repository:

sudo add-apt-repository ppa:mjasnik/ppa

b.) Install Timekpr-next:

Next, open terminal and run command to install the app in all Ubuntu releases or Debian 11:

sudo apt install timekpr-next

2. Set Time Limit for Your Kid’s Account:

Now, search for and open the time managing app from activities overview (or start menu depends on your desktop environment). There are two app icons, choose the one has “(SU)” at the beginning, which is available only for Administrator accounts.

Open (SU)Timekpr-Next

When the app opens, choose the child account under “Username” to configure. In the first tab, you can see the spend & left time info for the account. And, you may add/subtract specific hours/minutes for today’s time.

Under “Limit configuration” page, you may specify how many hours and minutes allowed to use each day. By adding “Hour intervals“, kids can only use the PC with limited hours/minutes during the interval.

NOTE: if “” checkbox is enabled, your kid is free to play during all the time interval without counting week day limits.

Saturday allows 1 hour during 00:00 ~ 22:00. And free to use from 22:00 to 24:00.

After setting the time limits, remember to click “Apply daily limits” to save changes.

For the PlayTime, it’s a time limit for running a certain app/process. You may use the feature to control how long your kid is allowed to play a game during the daily time limits, though it’s not enabled by default.

By default, the app will NOT count the time if the screen is locked or child is logging into command console (TTY console via Ctrl+Alt+F3 ~ F6). However, you may change this behavior via additional options:

There are many other settings, just move the cursor over an option it will prompt what does it do for you.

☐ ☆ ✇ UbuntuHandbook

HP Linux Printer Driver HPLIP 3.21.10 Adds Debian 11, Zorin OS 16 & Ubuntu 21.10 Support

By: Ji m

HPLIP, HP’s inkjet and laser printers Linux driver, released version 3.21.10 with new devices and Linux distributions support.

Zorin OS, the modern Ubuntu-based Linux distribution, is finally supported by HPLIP’s official .run installer. And, it also adds Debian 11 and Ubuntu 21.10 support.

As well, HPLIP 3.21.10 adds a list of new printers support:

  • HP ENVY Inspire 7200e series, 7900e series
  • HP LaserJet MFP M140a, MFP M139a, MFP M141a, MFP M142a, MFP M140w, MFP M140we, MFP M139w, MFP M139we, MFP M141w, MFP M141we, MFP M142we, MFP M142w
  • HP LaserJet M109a, M110a, M111a, M112a, M109w, M109we, M110w, M110we, M111w, M111we, M112we, M112w
  • HP DesignJet Z6 Pro 64in
  • HP DesignJet Z9 Pro 64in
  • HP PageWide XL Pro 5200 PS MFP series
  • HP PageWide XL Pro 8200 PS MFP series
  • HP PageWide XL 3920 MFP
  • HP PageWide XL 4200 Printer, 4200 Multifunction Printer
  • HP PageWide XL 4700 Printer, 4700 Multifunction Printer
  • HP PageWide XL 5200 Printer, 5200 Multifunction Printer
  • HP PageWide XL 8200 Printer

Download & Install HPLIP 3.21.10:

1. Firstly, download the .run installer package from the link page below:

2. Next, open terminal from start menu (Ubuntu may press Ctrl+Alt+T on keyboard to open it). When it opens, add executable permission to the .run packge:

chmod u+x ~/Downloads/hplip*.run

3. Finally, run the installer to start installing the Linux driver:


Follow the terminal output to answer some questions. When everything’s done, plug or re-plug your HP printer and enjoy!

For Ubuntu with python-pyqt5 dependency issue, this tutorial may help.

How to Remove HPLIP:

The release somehow does not create source folder while installing process. You may re-run the installer with --target flag to extract source:

~/Downloads/ --target ~/Downloads/hplip-3.21.10

When you see the new folder generated in Downloads, type q or press Ctrl+C to quit installer.

And, finally run the uninstall script from that folder will remove the driver:

sudo python3 ~/Downloads/hplip*/

That’s all. Enjoy!

☐ ☆ ✇ UbuntuHandbook

Firefox 94.0 Released with “Unload” option to Release System Resource

By: Ji m

Mozilla Firefox web browser released version 94.0. Here’s what’s new.

On the first launch of Firefox 94, a dialog will pop-up allows you to choose between color schemes. By clicking on “Explore colorways“, it allows to choose between 6 color palettes with live preview. And each has ‘Soft’, ‘Balance’, and ‘Cold’ colors to choose from.

For those using Mesa driver >= 21, Firefox 94 now uses the Linux graphics stack EGL instead of GLX. This will increase WebGL performance and reduce resource consumption. Ubuntu 21.04 and Ubuntu 21.10 may have the benefit, though proprietary Nvidia driver is not supported at the moment.

The new Firefox introduced a “about:unloads” page, allows users to manually unload inactive tabs to release system resources. Though it can be disabled by settings “browser.tabs.unloadOnLowMemory” to false.

Firefox about:unloads page

Other features in Firefox 94 include:

  • Firefox macOS now uses Apple’s low power mode for fullscreen video to extend battery life.
  • Firefox won’t prompt updates in Windows. Instead, it will download and install updates in background.
  • Introduced new Site Isolation security architecture.
  • Roll out Firefox Multi-Account Containers extension with Mozilla VPN integration
  • No longer warn when closing Firefox using a menu, button, or three-key command.
  • Support new Snap Layouts menus in Windows 11.
  • Reduced system resource usage and various security fixes.

Get Firefox 94:

For all current Ubuntu releases, including Ubuntu 18.04, Ubuntu 20.04, Ubuntu 21.04, and Ubuntu 21.10. It recommends to wait until the official Ubuntu builds released (check here).

It will be available to install in next few days through “Software Updater”:

For the portable Linux tarball as well as release note, go to mozilla website.

☐ ☆ ✇ UbuntuHandbook

Check Contrast between Two Colors in Ubuntu Linux via Kontrast

By: Ji m

For designers want to check color contrast, there are a few handy little tools in Linux Desktop to do the job. Kontrast is the one designed for KDE though works on all Linux desktops.

GNOME has a stylish color contrast tool. Though it’s now in early stage which does not work well and freezes often at least in my case. Here I’ll introduce the KDE’s Kontrast.

This little app displays font color for text and another color as background. Users may change the font and background colors by:

  • manually input a color value.
  • use built-in color picker.
  • drag slider bar to change hue, saturation, and lightness.
  • or use “Randomize” button to generate a pair of colors.

For each color combination, it displays the contrast ratio, and readability (“Perfect”, “Good”, or “Bad”) for normal and large text. There’s also “Invert” button to reverse the two colors. As you can see, it allows to mark color as favorite, though it somehow always fail in my case.

How to Install Kontrast in Ubuntu via apt:

For Ubuntu 21.04 and Ubuntu 21.10, this handy tool has been made into official Ubuntu repositories. Simply press Ctrl+Alt+T on keyboard to open terminal and run command to install it:

sudo apt install kontrast

Though for non-KDE desktop, there will be a lot of dependency libraries also to be installed.

Install Kontrast in Ubuntu 20.04 and older versions:

Ubuntu 20.04, Ubuntu 18.04, and even Ubuntu 16.04 users may install the latest version using the Linux universal flatpak package.

1.) Firstly, press Ctrl+Alt+T on keyboard to open terminal. Then run command to install the flatpak daemon:

sudo apt install flatpak

Ubuntu 18.04 and 16.04 need to add this stable PPA first.

2.) Next, add the flathub repository that hosts the package:

flatpak remote-add --if-not-exists flathub

3.) Finally install the color contrast checker app via command:

flatpak install flathub org.kde.kontrast

For first time installing KDE app as flatpak, there are almost 800 MB run-time libraries to be installed:

Once installed, search for and open the tool from activities overview screen and enjoy!

How to Remove Kontrast:

To remove the package installed via apt, use command:

sudo apt remove --autoremove kontrast

For the flatpak, use this command instead to remove it:

flatpak uninstall --delete-data kontrast

And run flatpak uninstall --unused command will delete the unused run-time libraries.