For those don’t like the Flatpak package, here’s how to install GIMP 2.99.6 from PPA in Ubuntu 20.04 LTS.

The popular GIMP image editor is working on the next major 3.0 release. For testing purpose, GIMP 2.99.6 was released as the latest development version. It provides the official Linux package via Flatpak package. However, some users don’t like it, since Flatpak is an universal package format needs separate daemon to run in sandbox.

Install GIMP 3.0 Dev from PPA in Ubuntu 20.04:

For Ubuntu 20.04 and derivatives, e.g, Linux Mint 20 and Zorin OS 16, the unofficial PPA contains the classic .deb package for GIMP 3.0 Dev release.

NOTE: The package in the PPA is unstable. It may have bugs and used only for testing purpose. Installing GIMP from this PPA will override the 2.10 stable release, don’t install it on production machine.

1. Add the PPA.

Press Ctrl+Alt+T on keyboard to open terminal, or search for and open terminal from start menu if you’re on Linux Mint or ZorinOS.

When terminal opens, copy and paste the command below and hit Run to add the PPA:

sudo add-apt-repository ppa:mati75/gimp30

Type your password as sudo command need user authentication, and hit Enter to continue.

2. Update package cache

Since Ubuntu 20.04, it updates the system package cache automatically while adding Ubuntu PPAs, However, Linux Mint 20 does not. So you may need to manually run command in terminal to update cache:

sudo apt update

3. Install / Upgrade to GIMP 3.0 Dev

Finally, you can either open Software Updater (Update Manager) to install or upgrade the GIMP package, or run command in terminal instead:

sudo apt install gimp gegl

Revert to GIMP 2.10 Stable:

It’s possible to downgrade the image editor back to 2.10 stable release, 2.10.18 if no other relevant PPA added.

Simply open terminal and run the command below to install the ppa-purge package, and then purge the Ubuntu PPA which will remove it as well as downgrade installed packages:

sudo apt install ppa-purge && sudo ppa-purge ppa:mati75/gimp30

That’s all. Enjoy!

Mozilla Firefox 92.0 was released today with new features and various security fixes.

The release will use HTTPS resource record (HTTPS RR) as Alt-Svc headers to make connections more secure.

The full-range color (0-255) levels are now supported for video playback. Though the limited color range (16-235) is ideal for movies and TV, the source can be switched to full-range color to match PC monitor.

For Mac, users can now access the macOS share options from the Firefox File menu. And it enables support for images containing ICC v4 profiles.

Other changes include:

  • Firefox performance with screen readers and other accessibility tools is no longer severely degraded if Mozilla Thunderbird is installed or updated after Firefox.
  • macOS VoiceOver now correctly reports buttons and links marked as ‘expanded’ using the aria-expanded attribute.
  • An open alert in a tab no longer causes performance issues in other tabs using the same process.
  • The bookmark toolbar menus on macOS now follow Firefox visual styles.
  • Certificate error pages have been redesigned for a better user experience.

How to Install Firefox 92:

Usually, Ubuntu will publish the new Firefox package in next few days. The best choice is just wait!

You’ll see the packages in Software Updater once published:

Or see the release note & download the Linux portable package from this page.

This simple tutorial shows how to install Virtualbox Guest Additions in Ubuntu based systems, e.g., Linux Mint, Zorin OS and Elementary OS, with fix or workaround for common issues.

Guest Additions is a set of device drivers and system applications to install in Guest OS. It’s useful when you try to share folder and/or clipboard between guest and host, enable USB support etc. Installing the software suite is easy via a menu option. However, it might not function in some cases.

Install Guest Additions in the Normal Way

Firstly, start and login the Guest OS. Then go to VM menu “Devices -> Insert Guest Additions CD image“.

Usually, a pop-up dialog will open and prompt whether to run autorun script or not. Just click “Run” and it starts to install the guest additions after you typing user password in authentication dialog.

After installation, the additions will function in next boot of the Guest OS.

[Workaround] Unable to insert the virtual optical disk:

Sometimes it outputs an error “Unable to insert the virtual optical disk … into the machine …” when you click on the menu option in VM (VirtualBox Machine).

It happens in my case when trying to install the additions in Elementary OS 6. And it will pop-up an error dialog:

Don’t know why but do following steps will fix the issue in next Guest boot:

1.) Power off the Guest OS, then go to its Settings page. Under the Storage settings, remove the attached iso under Controller:IDE.

2.) Next add new optical drive, and click “Leave Empty” in the select dialog.

After saving the changes, start the Guest OS and try to install the additions again.

Manually Download & Install Guest Additions:

Nothing happens when clicking ‘Insert Guest Additions CD image’ option? You can download the iso, mount it, and install the Guest Additions manually.

1.) Firstly start the VirtualBox Machine, download the iso image for your VirtualBox edition, usually “VBoxGuestAdditions_x.x.xx.iso”, from the link button below:

2.) Next open the Downloads folder, right-click or (double-click) on the file and select to mount the iso image.

The dialog should pop-up allows you to select “Run” to install the additions. If not, go to the mounted folder from the left pane in file manager. Right-click on blank area and select ‘Open in Terminal‘ to open a terminal window and navigate to the directory automatically.

When terminal opens, run the .run installer manually via command:

sudo ./

That’s all. Enjoy!

HPLIP, Hewlett-Packard’s Linux imaging and printing software, released version 3.21.8 with new printers support.

The open-source HP printer and scanner driver add some new devices support. They are:

  • HP Smart Tank 500 series
  • HP Smart Tank 530 series
  • HP Smart Tank Plus 570 series
  • HP Smart Tank 7600
  • HP Smart Tank 750
  • HP Smart Tank 790
  • HP Smart Tank Plus 710-720
  • HP Smart Tank Plus 7000
  • HP Smart Tank Plus 660-670
  • HP Smart Tank Plus 6000
  • HP DeskJet Ink Advantage Ultra 4800 All-in-One Printer series

And Linux Mint 20.2, RHEL 8.4 and Manjaro 21.0.7 are officially supported according to the release note.

How to Install HPLIP 3.21.8 in Ubuntu:

The official installer package, ““, is available to download at the link below:

After downloaded the file, open the Downloads folder in terminal by right-clicking on blank area in that directory and choose ‘Open in Terminal.’

Open Downloads folder in terminal

When terminal opens, add executable permission to the file by running command:

chmod u+x

Then run the installer and follow terminal output to start installing the driver:


For the python-pyqt5 dependency issue, see this how to tutorial. Or, you can manually install the dependencies via command:

sudo apt-get install libcups2 cups libcups2-dev cups-bsd cups-client libcupsimage2-dev libdbus-1-dev build-essential ghostscript openssl libjpeg-dev libsnmp-dev libtool-bin libusb-1.0-0-dev wget python3-pil policykit-1 policykit-1-gnome python3-pyqt5 python3-dbus.mainloop.pyqt5 python-gi-dev python3-dev python3-notify2 python3 python3-reportlab libsane libsane-dev sane-utils xsane libavahi-client-dev libavahi-core-dev

And compile it from source folder (generated automatically once you run the .run file) via configure, make, sudo make install.

Uninstall HPLIP 3.21.8:

While installing the driver, it creates a source folder that contains an uninstall script. Until you remove that folder, you can run the script to remove HPLIP:

cd ~/Downloads/hplip-3.21.8/ && sudo ./

This is a step by step tutorial shows how to add “open as root (or administrator)” option in Pantheon file browser in Elementary OS 6 Odin.

Elementary OS now is at version 6.0 based on Ubuntu 20.04 LTS. For those looking for the “Open as Administrator” function to open system file via root user permission, or do copy & paste things outside of user’s home directory, things have changed.

The executable command for the file manager now is io.elementary.files, and the command to start text editor is io.elementary.code. Both are named in Flatpak app style. Gksu has gnone, and “pkexec” takes the place to allow an authorized user to execute program as root.

Add Open as Admin action in Elementary OS 6:

1. ) Firstly, search for and open “terminal” from the top-left corner Applications menu.

2. When terminal opens, run command to create (& edit via nano) the configuration file for option to edit file as root user privilege:

sudo nano /usr/share/contractor/

When the file opens in terminal, paste following lines and save via Ctrl+X, type y and hit Enter.

[Contractor Entry]
Name=Edit as Administrator
Description=Edit file via root user privilege
Exec=pkexec io.elementary.code %U

3. And create another config file for an option to open folder as root permission:

sudo nano /usr/share/contractor/

Then paste the following lines and save it (Ctrl+X, type y, and hit Enter):

[Contractor Entry]
Name=Open as Administrator
Description=Open a folder via root user privilege
Exec=pkexec io.elementary.files %U
Gettext-Domain=file manager

After creating the two files, “Edit as Administrator” and “Open as Administrator” context menu option appear when right-clicking a file or folder immediately without restart.

As you see, you can create more actions by creating files with “.contract” extension under /usr/share/contractor directory. The name will be displayed as menu option, and you can find value of icon, MineType and Exec by checking the app shortcut file (.desktop) under /usr/share/applications directory.

That’s all. Enjoy!