It will ask for your password, or you could use the above command with sudo.
Now, if you try to install a Fltapak package from Fltahub, it should work as expected.
Adding the Flathub repoistory fixes the issue
Reason why you see this error and how it was fixed
Now that have fixed the error, it would be a good idea to also learn why you saw this error in the first place and how it was fixed.
Like most other package managers in Linux, Flatpak also works on the concept of repositories. In simpler words, you can imagine package repositories as a warehouse where packages are stored.
But in order to retrieve a package from this warehouse, you need to know the address of the warehouse first.
That’s what happens here. You are trying to download (and install) a package from a certain repository (Flathub in this case). But your system doesn’t know about this “flathub”.
In order to solve this issue, you added the Flathub repository. When you do that, your Linux system can look for the package you are trying to install in this repository.
You may see all the remote Flatpak repository added to your system.
List Flatpak repositories added to your system
Let’s have a deeper look at the command which was used for adding the repository:
remote-add: this option indicates that you are adding a new remote repository.
–if-not-exists: this ensures that the remote repository is only added if it is not added already.
flathub: this is short reference for the complete URL of the actual repository. You may name it something else but the convention is to use the one provided by the developer.
https://ift.tt/2W91O0u The actual repository address.
So, the bottom line is that when you see Flatpak complaining about ‘no remote refs found similar to xyz’, verify that the said repository is not added and if that’s the case, figure out its URL and add it to the system.
I hope this quick tip help you with this Flatpak issue.
Android is built on top of a heavily customized Linux kernel. So, running mobile apps on Linux makes sense using an Android emulator.
While this is not something new that you can do on your Linux machine, it is a feature more in demand after Windows introduced the ability to run Android apps in 2021.
Not just limited to using apps, some of the Android emulators can also come in handy for development and testing.
Hence, I have compiled a list of the best emulators that you can use to test or run Android applications/games on Linux.
1. Anbox
Anbox is a pretty popular emulator that lets Linux users run Android apps. Probably this is what Deepin Linux utilizes to make help run Android apps out of the box.
It isolates the Android operating system from the host using a container, which also lets them make the latest Android version available to use.
Android apps running will not have direct access to your hardware—which is a good security decision.
Unlike some of the other options here, Anbox does not technically need an emulation layer to make Android work. In other words, it is as close to a native Android experience on your Linux system.
For this reason, it may not be the easiest option available. You cannot just use the Google Play Store to install applications, you need to utilize Android Debug Bridge (ADB). All you need is the APK file of an app to install and use it.
Genymotion is an impressive solution tailored for testing and development.
It is not a free and open-source option. They provide virtual Android experiences as a service through the cloud or a desktop client that is independent of Android Studio.
You can simulate a variety of hardware configurations and Android versions to create a virtual device for testing. It also gives you the ability to scale up and has multiple Android virtual devices running for extensive tests.
It can help you test how file uploading works in your app, impacts battery, performance, memory, and so on.
While it is a premium solution mostly for professionals, it does support the latest Linux distributions that include Ubuntu 20.04 LTS.
Android Studio is a full-fledged tool for development and testing. Fortunately, with the support for Linux, you can use it to emulate the Android experience for experiments if you need to.
You just need to create an Android Virtual Device (AVD) that you can configure and then simulate as an emulator.
There are good chances to find support for some of the latest smartphones, TVs, and smartwatches as well.
It needs a certain learning curve to be able to pull it off, but it is free and completely open-source.
An interesting solution is an Android emulator that you can use in Linux and any other platform.
It helps run Android apps on Chrome OS or with Chrome browser on any operating system. Unlike some others, you may not get a complete Android experience but only the ability to run Android apps.
You just have to unpack the runtime and load it into Chrome extensions. Next, add the app you want to use by downloading the APK file onto it.
Bliss OS is yet another open-source project, similar to Android x86 that aims to make Android run on PC.
Unlike Android x86, it gives more compatibility options by supporting both 32-bit and 64-bit architectures. Also, you can download the compatible file as per your processor.
It is actively maintained and supports the latest Android versions available in the market.
Swipe three fingers up on the touchpad and brings up the activity menu. Do it once more and you’ll have the application menu. Move the fingers down and you’ll be coming out of the application menu and the acitivity area.
Illustration of three fingers swipe in GNOME
Similarly, moving three fingers horizontally moves you to the next workspace on your right (or left).
I have installed Fedora 34 with GNOME 40 on my second laptop and experimenting with it in my free time. When I logged into the system after a few days, I realized that three fingers swipe was not working anymore.
If you are facing the same issue, here are a couple of methods to fix it.
Method 1: Use Wayland for three finger swipe in GNOME 40
Please make sure that you are using Wayland. To check, use the following command:
echo $XDG_SESSION_TYPE
If it shows x11, you’ll have to switch to Wayland. Save your work and log out of your system.
On the log in screen, click on your username. In the bottom right corner, you’ll see a gear symbol. Click on it. You should see a few options like GNOME, GNOME Classic and GNOME on Xorg. Go with GNOME which uses Wayland by default.
Switching between Xorg and Wayland
After selecting that, enter your password and log into the system. You should have the three fingers gesture working again.
The three fingers swipe works only in Wayland by default. It can be used in X display server as well but that requires some additional effort and I’ll show that to you in the second method.
Method 2: Using three fingers gesture with Xorg and/or GNOME 38 and higher version
If for some reasons, you must use X display server (Xorg), you could still make the three fingers swipe work with some additional efforts.
Built on top of GNOME’s JavaScript library and GTK4 toolkit, it blends naturally in the GNOME desktop environment. It uses GStreamer for media backend and OpenGL for rendering.
I like application with minimalist approach. While VLC is the Swiss Knife of media players, I prefer MPV player for the sleek, minimal interface. And now I think I am going to stick with Clapper for sometime.
Clapper doesn’t use the traditional upper window bar. There are auto-hiding preference menu, mode changer and window control buttons for you to access a few features. This gives it a sleek, minimalist look.
It has three modes:
Windowed mode: the default mode shows the progress bar and window control
Floating mode: the progress bar is hidden and the player is floating on top of other applications like the ‘always on top‘ feature or ‘picture in picture’ mode
Fullscreen mode: Player goes full screen, progress bar is bigger but they all auto-hide
Interface of Clapper video player with preference control and window modes
Clapper also has an adaptive UI which can also be used on Linux-based smartphones and tablets. So if you have got yourself a Pine Phone or Librem5, you can use Clapper on it.
There is support for subtitles with option to change the font. However, the subtitles didn’t work in my testing. There is also no option to explicitly add subtitles to a playing video. This is something that must be improved.
Like VLC, Clapper also gives you the option to resume playback from the last point if you open the same video file again. One of the handy features I love in VLC.
Clapper supports playing videos from the internet as well if you provide the URL.
Here, in the screenshot, I am playing a YouTube video in Clapper. It is a beautiful song sung by a beautiful singer and actress. Can you guess which song or movie it is?
Clapper playing a video from YouTube
Install Clapper on Linux
Clapper is available in AUR for Arch and Manjaro users. That should not be a surprise for anyone. AUR has everything under the sun.
There are hundreds of Linux distributions. Some are for general purpose usage, while some are specifically tailored for education, robotics, hacking, gaming and what not.
You’ll notice that most of them originate from Debian/Ubuntu, Arch and Red Hat/Fedora. If you like distrohopping and experiment with a range of distributions, you may soon get ‘bored’ out of it. Most Linux distributions would feel too similar after a point and apart from a few visual changes here and there, you won’t get a different experience.
Does that sound familiar? If yes, let me list some advanced, independent, Linux distributions to test your expertise.
Advanced Linux distributions for experts
You may argue against the use of term “expert” here. After all, ‘expert Linux users’ don’t necessarily need to use advanced Linux distributions. They can easily utilize their expertise on beginner-friendly distributions like Linux Mint.
The term expert here is intended for people who won’t easily get overwhelmed when they are taken out of their comfort zone and land in an unfamiliar environment.
Alright then. Let’s see which distributions you can use to test your expertise on.
NixOS
NixOS Linux illustration
NixOS is a unique distribution in the terms of how it approaches everything from the kernel to configuration to applications.
NixOS is built on top of the Nix package manager and everything from the kernel to configuration is based on it. All packages are kept in isolation from each other.
It ensures that installing or upgrading one package does not break other packages. You can also easily roll back to previous versions.
The isolation feature also helps you in trying new tools without hesitation, creating development environments and more.
Sounds good enough to give it a try? You call, truly.
Void Linux
Void Linux illustration
Void Linux is another independent Linux distribution which was implemented from scratch. It is a rolling release distribution but it focuses on stability rather than being bleeding edge like Arch Linux.
Void Linux has its own XBPS package management system for installing and removing software with option to build packages from sources (from XBPS source packages collection).
Another thing that sets Void Linux apart from the crowd of other distribution is its use of runit as init system instead of systemd.
Can Void Linux fill the void in your distrohopping life? Find it out yourself.
Slackware
Slackware Linux illustration
The oldest active Linux distribution, Slackware, can surely be counted as an expert Linux distribution.
Which is amusing because once upon a time, many new Linux users started their Linux journey with Slackware. But that was back in the mid-90s and it is safe to assume that those newbies have turned into veteran with their neck beard touching the ground.
Originally, Slackware was based on Softlanding Linux System (SLS), one of the earliest Linux distributions in 1992.
Slackware is an advanced Linux distribution with aim to produce the most “UNIX-like” Linux distribution out there.
No slacking here. Be ready to use the command line extensively in Slackware.
Gentoo
Gentoo Linux illustration
Gentoo Linux is named after the fast swimming Gentoo penguin. It reflects the speed optimization capabilities of Gentoo Linux.
How? It’s software distribution system, Portage, gives it extreme configurability and performance. Portage keeps a collection of build scripts for the packages and it automatically builds a custom version of package based on end user’s preference and optimized for end user’s hardware.
This ‘build’ stuff is why there are many jokes and meme in Linux-verse about compiling everything in Gentoo.
Can you catch up with the Gentoo?
Clear Linux
Clear Linux illustration
Clear Linux is not your general purpose desktop Linux distribution. It is an open source, rolling release distribution, created from the ground up by Intel and obviously, it is highly tuned for Intel platforms.
Clear Linux OS primarily targets professionals in the field of IT, DevOps, Cloud/Container deployments, and AI.
The package management is done through swupd but unlike regular package managers, versioning happens at the individual file level. This means that it generates an entirely new OS version when any software change takes place in the system.
Is it clear enough to try Clear Linux?
Linux From Scratch
Linux From Scratch illustration
If you think installing Arch Linux was a challenge, try Linux From Scratch (LFS). As the name suggests, here you get have to do everything from scratch.
From installing to using, you do everything at a low level and that’s the beauty of it. You are not installing a pre-compiled Linux distribution here. You build your own customized Linux system entirely from the source code.
It is often suggested to use Linux From Scratch to learn the core functioning of the Linux and it is indeed a learning experience.
There are a few more independent Linux distributions. Mageia and Solus are two of the relatively more popular ones. I did not include them in this list because I consider them more friendly and not as complicated to use as others on the list. Feel free to disagree with me in the comments.
It is your turn now. Have you used any advanced Linux distributions ever? Was it in the past or are you still using it?
Can kids use Linux distributions? And is it suitable for school use?
Well, that depends on what are your options and what you choose to go with. No matter whether you want something for a kid or the school teacher, there are options available.
Hence, to give you a head start, we have curated a list of best Linux distributions tailored for education.
Best Linux Distribution for Kids
For a kid, a distribution has to offer a user-friendly UI minus the advanced functionalities.
You may argue that it can be done with any mainstream, beginner-friendly distro like Ubuntu, Mint or Zorin. You are right, but if a distribution comes with essential tools baked in and makes it easy to use, kids will quickly learn to use it and have fun.
1. Endless OS
Image Credits: Distrowatch
Endless OS is a popular option to go for as a Linux distro tailored for education.
It is based on Debian and uses GNOME desktop environment. Even though it restricts usage of its OS on more than five hundred computers in a year, it is free to download.
The user interface is easy to use and looks attractive for installation in a modern PC. You get variety of applications pre-installed. Hence, this comes handy for computers with no internet access.
Ubermix is an Ubuntu-based Linux distribution that aims to reduce the complexity by tweaking the user interface, getting rid of unnecessary apps, and adding essential tools/apps for education.
It also offers a way to easily recover from a system issue in case there is a problem. An optional parental control feature is present for content filtering and screen time controls, which is indeed useful.
Ubermix is actively maintained and provides plenty of instructions for installation and troubleshooting on its official website.
Kano is a computing kit tailored for educating children from 6 to 14 years. It’s like a premium version of Raspberry Pi with plenty of DIY and coding activities for the young ones.
Kano also has Debian based operating system for Raspberry Pi. You don’t need to have Kano kit for this purpose. You can use it on your Raspberry Pi.
It aims to provide the benefits of it—curated for education when coupled with their computer kits. Ranging from coding apps to games, there should be something for everyone.
You will also find useful parental control settings to limit/tweak the experience for your kid. For additional help, the official help resources will come in handy as well.
Yet another distribution based on Debian focused for learning.
Not just for primary-level education, but the programs included in the operating system should be useful for university students as well. It also includes virtual interactive labs and virtual microscope.
While it makes learning easy with the utilities pre-installed, teachers can also use it to create content and publish.
So, it can be an all-in-one choice for a lot of potential learners and teachers in school.
Linux for education (Li-f-e) was originally a project by OpenSUSE and this is a continuation of that.
Even though it is not backed by OpenSUSE now (I couldn’t find any references), it could be a useful option for kids and schools.
This is based on Ubuntu MATE and offers several built-in applications as per some of the textbooks. It does not offer anything extraordinary but more like Ubuntu for education, which is actively maintained at the time of writing this.
The ones I mentioned so far were tailored to be used by children for their education and learning. But education has two parts: students and teachers.
This is why this list is divided into two parts. This second part lists some options that can be a good fit for school administrators, management, and teachers.
Of course, you can always use Linux Mint, elementary OS, or Ubuntu if you want to utilize a stable and reliable Linux desktop OS to manage your school (or) content creation. However, there are some choices that are customized for the purpose.
1. Debian Edu/Skolelinux
Image Credits: Distrowatch
Skolelinux is a Debian-based distribution that comes packed with several applications and networking services fit for students and teachers in school.
It is also known as Debian Edu. You get the ability to opt for offline installation by downloading the required ISO or the base system with online installation for the rest.
Even though kids can use it after setup, it requires a bit of learning curve to configure and maintain. Hence, this is more inclined towards school administrators or teachers than kids.
A Linux distribution with the perks of Ubuntu LTS built for school servers. If you want to setup a server and monitor/control a network of connected servers, Linux Schools (or Karoshi Server) is a good fit.
It lets you administer a network of servers using a web interface. You do not need in-depth knowledge about Linux system administration to utilize it.
Escuelas Linux is based on Bodhi Linux. It comes baked in with several applications fit for educational environments.
It has custom tools for resetting the distro in the post-installed state in seconds. There is also options to reinstate users. Apart from that, it comes with applications for distributing educational material within the network, screen broadcasting, mirroring, remote command execution, message sending, screen locking and muting sound to the students’s computers.
Considering it is based on Bodhi Linux, which is one of the best lightweight Linux distros, this can be a good pick for older systems.
You also get an added developer pack, which is optional to install, if you need advanced tools like NetBeans, Git, Android Studio.
In addition to these options, there is also EduBOSS, an education version of BOSS Linux which is tailored for Indian schools, if that is relevant to you.
Wrapping Up
While there are 100s of Linux distribution, only a handful exist that are specially crafted for education.
It is a good thing that there some viable options for students, teachers, and school administration.
After all, Linux can be used everywhere and by anyone. Am I right?
Converseen is a free and open source software for batch image conversion. With this tool, you can convert multiple images to another format, resize, change their aspect ratio, rotate or flip them all at once.
This is a handy tool for someone like me who has to deal with multiple screenshots of different size but has to resize them all before uploading to the website.
Batch conversion tools help a lot in such cases. This could be done in the Linux command line with the wonderful ImageMagick but a GUI tool is a lot easier to use here. Actually, Converseen uses ImageMagick underneath the Qt-based GUI.
Batch process images with Converseen
You can use Converseen to convert, resize, rotate and flip multiple images with a mouse click.
You have plenty of supporting options for the batch conversion. You can add additional images to your selection or remove some of them. You can choose to convert only a few of your selected images.
While resizing the images, you can choose to keep the aspect ratio. Keep in mind that out of width and height, the one you changed/typed last is the one controlling the aspect ratio. So, if you want to resize keeping the same aspect ratio but according to the width, don’t touch the height field.
You can also choose to save the converted images with different name in the same directory or some other location. You may also overwrite the existing images.
You cannot add folder but you can select and add multiple images at once.
You can convert the images to a number of formats like JPEG, JPG, TIFF, SVG and more.
There is also an option to give the transparent background a certain color while changing the format. You can also set the quality of the compression level.
Converseen says that it can also import PDF files and convert the entire PDF or part of it into images. However, it crashed in Ubuntu 21.04 each time I tried to convert a PDF file.
Install Converseen on Linux
Converseen is a popular application. It is available in the repositories of most Linux distributions.
You can search for it in your distribution’s software center:
You may, of course, use your distribution’s package manager to install it via command line.
On Debian and Ubuntu-based distributions, use:
sudo apt install converseen
On Fedora, use:
sudo dnf install converseen
On Arch and Manjaro, use:
sudo pacman -Sy converseen
Converseen is also available for Windows and FreeBSD. You can get the instructions on the download page of the project website.
Overall, Converseen is a useful GUI tool for batch image conversion. It’s not perfect but it works for the most part. Have you ever used Converseen or do you use a similar tool? How is your experience with it?
