Author Archives: Lorenzo Bettini

About Lorenzo Bettini

Lorenzo Bettini is an Associate Professor in Computer Science at the Dipartimento di Statistica, Informatica, Applicazioni "Giuseppe Parenti", Università di Firenze, Italy. Previously, he was a researcher in Computer Science at Dipartimento di Informatica, Università di Torino, Italy. He has a Masters Degree summa cum laude in Computer Science (Università di Firenze) and a PhD in "Logics and Theoretical Computer Science" (Università di Siena). His research interests cover design, theory, and the implementation of statically typed programming languages and Domain Specific Languages. He is also the author of about 90 research papers published in international conferences and international journals.

Taming KDE baloo

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Quoting from https://community.kde.org/Baloo,

Baloo is the file indexing and file search framework for KDE Plasma, with a focus on providing a very small memory footprint along with extremely fast searching.

Unfortunately, it has a bad reputation for being a resource hog. However, it all boils down to configuring it appropriately (of course, according to your needs), and not only will it be “tamed”, but it will also work fast, using a few resources, and it will be your friend when using KDE.

In this article, I describe how I configure it to be fast and functional without being a resource hog.

I anticipate that I use baloo only for file search, NOT content searching. I don’t think baloo is the best tool under that concern because it updates its index continuously. For content searching, I suggest Recoll. You can configure Recoll to update the index a few times daily, which is typically enough. Moreover, Recoll provides more powerful query mechanisms for content searching than baloo. If you want baloo to index file contents, remember that this requires more resources and time to complete.

First of all, configuring baloo should be the first thing you do after you install KDE and log in to KDE for the first time. At least, it would be best if you disabled it before filling your home folder with all your contents.

Whether baloo is enabled or disabled by default depends on the distribution. Go to System Settings -> Search -> File Search.

In this example, it’s disabled. Let’s check “Enable File Search” and uncheck “Also index file content” (at least, I disable indexing of file contents for the reasons I said above). DON’T PRESS “Apply” yet. Another problem with the default configuration is that it will index all the files in your home folder. That’s probably too much unless you want to search everywhere in your home folder (including temporary files, locally installed binaries, etc.).

In that respect, I prefer to exclude my home folder and provide some subfolders to be indexed. So I use the dropdown menu and exclude my home folder:

Then, I add the folders I want to be indexed with the button “Start indexing a folder…”:

Now, you can hit “Apply”, and after some time, you can see that indexing completes. With an SSD and indexed folders that do not contain many files, it takes baloo just a moment to index the selected folders.

You may also want to learn to use the command balooctl from the terminal to have more control over baloo and retrieve indexing information. For example, here’s an example of the status subcommand and its result on my system after the configuration above and after the indexed directories are filled with my data:

Learning more about baloo configuration to have fine-grained control of its indexing functionality is even better. For example, you can refine the configuration by excluding some files from the specified indexed folders based on their extensions or with regular expressions. As far as I know, you cannot do that from the system setting’s dialog shown above. You have to tweak the configuration file ~/.config/baloofilerc.

The interesting part is “exclude filters=…” where you specify a comma-separated list of regular expression for excluding files or folders. It comes prefilled with some sensible values for exclusions. You can add your own exclusion filters.

After modifying this files, I’d suggest you rebuild the index with this command:

After the index is recreated, many files have been excluded:

You can enjoy baloo file search from the “Search” in the “Application Menu” and from “KRunner” (Alt+space). In that respect, KRunner might take some time before it correctly shows the indexed files after a re-index.

Now, baloo is tamed and you can enjoy its features without losing your resources.

Final thoughts: for you sure, you must make sure things like BTRFS snapshots don’t end in the folders to be indexed, or you will have several problems, including lots of resource usage not to mention duplicate results during the search.

Fixing Docker problems in Fedora

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In this post, I’ll describe a few problems with Docker in Fedora and how to fix them. In particular, I’ll try to provide an analysis of the problems and the sources of the solutions.

I’ve experienced a few problems with Docker in Fedora (35 and 36). I first installed docker-ce by following the official documentation: https://docs.docker.com/engine/install/fedora/. Things went smoothly at the beginning with the first Docker images, e.g., the “hello-world”, “ubuntu,” and a few others.

However, I started to experience severe problems with this image “mysql:5.7”: the container took a lot of time to start, and I noted that Docker immediately ate my whole RAM, 16 Gb. If I don’t terminate the process, the computer will likely hang in a minute or less.

This is a docker-compose file to recreate the problem:

Save it to “docker-compose.yaml” and start it with “docker-compose up” and see the problem.

You must install the package docker-compose from Fedora’s repositories to verify the problem. I anticipate that the problem is not due to docker-compose because I have precisely the same problems with the above Docker image even if I run it without docker-compose (e.g., during a Maven build).

There’s no problem with a more recent version of the MySQL image, e.g., “mysql:8.0.27”. However, there’s something wrong with Docker in Fedora because the same docker-compose file using “mysql:5.7” does not give me any problem and works perfectly in other Linux distributions like Ubuntu and Arch.

I also experienced slow performance and ram draining when running an ansible molecule test with one of my ansible playbooks, e.g., running a flatpak installation in a Docker container. Again, only in Fedora.

I reported here https://ask.fedoraproject.org/t/docker-very-slow-in-fedora/23214 without getting any solution.

Here are the solutions I found myself.

Use moby engine (and tweak its configuration)

Instead of using “docker-ce”, I tried moby-engine (https://mobyproject.org/), which provides the same “docker” command line tools. The existing docker-compose works with moby as well. As stated here https://fedoramagazine.org/docker-and-fedora-35/, moby-engine is the “Fedora’s way” (though the official Docker package is said to work as well).

Surprise! the above docker-compose file works like magic: it starts fast and does not eat RAM. Also, my ansible molecule tests work perfectly.

Unfortunately, you run into problems using the excellent Testcontainers library. This problem is due to SELinux (that figures!!!). You can use this example project (taken from my TDD book): https://github.com/LorenzoBettini/it-docker-mongo-example. If you have Java and Maven installed, you can clone the repository, enter the directory “com.examples.school,” and run “mvn verify”. When it comes to Testcontainers tests, you get errors of this shape:

If you temporarily disable Selinux:

The Testcontainers tests will succeed.

However, let’s try to fix this problem once and for all.

To understand why moby-engine’s docker command works while docker-ce’s docker does not I inspected the version of the file /usr/lib/systemd/system/docker.service file provided by the moby-engine’s installation and the version provided by docker-ce’s installation.

These are the interesting parts of the docker.service file that comes with the moby-engine package:

While these are the corresponding parts in the version of the file provided by the docker-ce package:

The main differences are:

  • docker-ce uses a simple command to start the Docker daemon
  • moby-engine passes more arguments and relies on additional arguments (the OPTIONS environment variable) read from the additional file /etc/sysconfig/docker, whose contents are listed here:

First, I like this approach of relying on a separate file, which the user can customize. I understand that updates to the moby-engine package will not overwrite this file.

Thus, to avoid the Selinux problem with Testcontainers, it is enough to remove the “–selinux-enabled” argument in the above file. These are the steps:

  • Stop docker, “sudo systemctl stop docker”
  • Modify the file as follows:

  • Restart docker “sudo systemctl daemon reload && sudo systemctl start docker”

Moreover, disabling SELinux in the above file is also required if you, like me, prefer to have the docker directory (by default, it is /var/lib/docker) in another place (e.g., in a standard partition, which is not BTRFS and which is shared among several Linux distributions on the same computer).

Here’s an example of customization of the above file to tell Docker to use a different root directory:

If you use a different root directory with SELinux enabled, you might get errors when running containers of the shape

Fixing docker-ce

By taking inspiration from the configuration of moby-engine, we can also fix docker-ce by tweaking its configuration.

Of course, stop the Docker service (“sudo systemctl stop docker”) before doing the following steps.

It makes no sense to modify the file /usr/lib/systemd/system/docker.service directly because that will be overwritten by docker-ce package updates (I’m sure about that: I’ve seen it).

Instead, we first create the file /etc/sysconfig/docker (which does not exist in docker-ce installation) by removing a few arguments that would not work in docker-ce:

Then, we create another service file to specify the Docker daemon execution command:

And these are the contents of the created file:

Restart docker “sudo systemctl daemon reload && sudo systemctl start docker”. Everything should now work with docker-ce!

Of course, this approach also works with a specified “–data-root” argument, as seen in the moby-engine example.

Conclusions

On a side note, it might be enough to use only a subset of arguments in the docker-ce configuration taken from moby-engine. However, I think I wasted enough time debugging these problems in Fedora, and for the time being, I’m happy with these existing configurations.

I also want to stress my disappointment about how Fedora makes developers’ lives hard in these situations. I decided to debug these Docker problems and find solutions as a challenge. However, my interest in Fedora and my initial appreciation for this distribution significantly decreased. I won’t stop using it shortly, but I will not use it as my daily driver. For that, there’s Arch! 🙂

VirtualBox in Fedora Linux

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I have no problem installing VirtualBox and the related tools and extensions in Ubuntu and Arch. In Fedora, things are a little bit harder.

First, I think it’s better NOT to download binaries distributed by VirtualBox: I’m using Fedora packages that are available from RPM Fusion Free. Thus, first of all, you have to enable such a repository.

Then you run

It’s also best to add your user to the VirtualBox group:

And reboot, of course.

Then, to have additional features, you should install the VirtualBox extension pack. That’s where Fedora gets complicated. Differently from Ubuntu (package virtualbox-ext-pack) and Arch (package virtualbox-ext-oracle), you will not find a corresponding package in the RPM Fusion repositories.

You need to download the file from the VirtualBox website manually, http://download.virtualbox.org/virtualbox/. You must download a file of the shape Oracle_VM_VirtualBox_Extension_Pack-<VERSION>.vbox-extpack where <VERSION> must match the version of VirtualBox you installed. Then, you install it inside VirtualBox with File => Preferences => Extensions.

If the versions don’t match, you will have trouble starting your virtual machines with errors of the shape:

I experienced such a problem and asked on the Fedora forum.

Then, I realized that VirtualBox had been upgraded during a system update, but I forgot to download and install the updated extension pack. You can see the versions don’t match:

I then downloaded the corresponding file http://download.virtualbox.org/virtualbox/6.1.38/Oracle_VM_VirtualBox_Extension_Pack-6.1.38.vbox-extpack. And added it to the “Extensions” preference (selecting “Upgrade”):

That was enough to go back to running my VirtualBox machines.

However, I must admit that the whole procedure for using VirtualBox in Fedora is much more cumbersome and error-prone than in other distributions 🙁 It’s far too easy in Fedora to forget about package upgrades that require manual interventions. In general, I’d like to avoid manual interventions at all 😉

Again woes for KDE and Google Accounts

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TL;DR If you want to access your Google Calendars from Korganizer or Kalendar, remember to enable “Enable the KDE wallet subsystem”.

I had already written about the cumbersome procedure to access Google accounts in KDE, and I thought I had learned enough to “easily” set my Google calendars in KDE. I was wrong. Today I tried KDE again (I’m mainly a GNOME user for the moment) in a brand new Arch-based installation. I also decided to try the new calendar application, Kalendar. I managed to add a new calendar by selecting “Google Groupware”:

(By the way, once you selected “Google Groupware”, can you spot any “Add”, “OK”, or any other way to confirm the selection? There’s “Close”, but I’d assume that is for canceling the selection… IIRC, you must double-click on the selection; anyway, that’s odd!)

But then, I couldn’t configure it: I pressed the button “Edit,” and nothing happened!

I mean, no error pop-up. Nothing printed on the console if I ran Kalendar from the command line. Nothing in the journalctl log. NOTHING!

The same happens with Korganizer. The Google Groupware calendar already appeared because Kalendar and Korganizer share the same calendars. The problem is still there: the calendar is not configured and clicking “Modify” led to nothing. No error. NOTHING again!

To cut a long story short: you must enable the wallet subsystem in the KDE system settings:

How could it be possible? In 2022, KDE and its programs cannot cooperate in providing meaningful information when something goes wrong! And in KDE, things often go wrong.

For example, it’s been more than one year since KAddressBook cannot access Google’s address book! https://bugs.kde.org/show_bug.cgi?id=439285.

SSH into a VirtualBox machine

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I use VirtualBox a lot for testing purposes, mainly to experiment with a Linux distribution (to see whether it’s worthwhile to install it on bare metal) and to test procedures that might involve some complex (and maybe “dangerous”) operations.

After you install VirtualBox Guest Additions, things like bidirectional copy-and-paste will work. Some distributions seem to enable and install such additions right from the start (e.g., Fedora, if I’m not wrong). However, there are many situations where you’re installing a distribution in a VirtualBox machine. If Guest Additions are not already working, you will not be able to copy and paste anything. For example, the ISO of Arch Linux even comes in textual mode only, and it’s helpful to be able to copy and paste commands.

In such situations, I prefer to SSH into the virtual machine from a local terminal: copy and paste will work (since I’m in a local terminal). Moreover, the keyboard layout will be the one of the local system (the host). Thus, the keyboard layout will be already configured correctly. While in the virtual machine, you’d have to configure the keyboard layout. Finally, you can quickly transfer files via SSH between the host and the virtual machine without configuring shared folders.

Before being able to SSH in a virtual machine, you need two things:

  • An SSH server up and running in the virtual machine (how to do that depends on the specific Linux distribution)
  • Configure port forwarding in the virtual machine: for instance, all connections to a specific port on the host will be forwarded to port 22 (the default SSH port) on the virtual machine.

I could do the second operation through the “Settings” of the machine. That requires a few dialogs and filling a few table cells. However, I prefer to do that with a single command from the host. For example, I create and configure a new virtual machine, let’s say with the name “My Machine”. When it is not running, I run from the host:

Then, when I start the virtual machine, assuming the SSH server is configured in the virtual machine, I SSH into the machine through the local port 2522. Of course, you can choose any free port number on your host. For example, assuming there’s a user foo in the virtual machine, I run:

Let’s see a complete example.

Let’s say I create a virtual machine called “Arch Gnome” for installing Arch Linux. I configure it appropriately. In particular, I “insert” the ISO of Arch Linux into the virtual CD ROM drive of the machine. Before starting the machine, I run from the host:

Start the virtual machine:

Inside the live environment of Arch Linux, the SSH server is already up and running. However, since we’ll connect with the root account (the only one present), we must give the root account a password. By default, it’s empty, and SSH will not allow you to log in with a blank password. Choose a password. This password is temporary, and if you’re in a trusted local network, you can choose an easy one.

Now, we can connect via SSH to the virtual machine through localhost. If you have already connected via SSH to localhost, you might get an error of the shape:

All you have to do is edit the known_hosts file by removing the offending lines and try again. You will have to remove all the lines that start with “[127.0.0.1]:2522”.

Note that we’re using port 2522 because we previously used that for creating the port mapping. Let’s connect to the virtual machine and type the password we have previously specified for the root account inside the virtual machine (Accept the fingerprint, when asked.):

In your local terminal, you see that you get the colors of the virtual machine (now, you’re inside the virtual machine):

The keyboard layout is the one of the host; as usual, you copy and paste the text into the local terminal and run commands in the virtual machine, but more comfortably since you’re in your local terminal. You can also transfer files with “scp”.

For transferring files, you could also configure your file manager to access the “remote” server (the virtual machine) and browse and perform operations on the virtual machine’s file system from your local file manager.

Some benchmarks for building an Eclipse project: Linux, Windows, macOS (M1)

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I want to share some benchmarks for building an Eclipse project with Maven/Tycho. I built the project on Linux, Windows, and macOS (in particular, on my Mac Air M1 2020).

I stressed that the macOS environment is an M1, the new Arm-based chip from Apple, which is said to be quite efficient and performant. However, I also used an older Mac Air 2016, so no M1 here.

Concerning Linux and Windows, I used an LG GRAM 16. Both are good machines with powerful processors, 16Gig RAM, and NVMe disk. I ran the same build on a few Linux distributions (Arch, Ubuntu, Fedora) and the results concerning Linux are basically the same.

The Eclipse project is Edelta, https://github.com/LorenzoBettini/edelta, “An Xtext DSL for EMF metamodels refactoring and migration.” It’s quite a complex project with an extensive test suite: unit tests, integration tests (JUnit Plug-in tests), and SWTBot tests. The project also includes a custom Maven plugin, which is also tested. Yes, I’m test-addicted 😉

To avoid the Internet connection influencing the benchmarks, I first run the Maven build once so that Maven downloads and caches all the dependencies. Moreover, I first mirrored the p2 Eclipse artifacts so that the target platform definition is resolved against the local mirror.

LG GRAM 16 (LINUX) Total time: 03:25 min

LG GRAM 16 (WINDOWS) Total time: 04:20 min

MACBOOK AIR M1 Total time: 02:49 min

MACBOOK AIR 2016 Total time: 08:17 min

I must say I was impressed by the best performance shown by the M1 processor!

As expected, on the same machine, Windows performs worse than Linux 🙂

The performance of the old Mac Air is not impressive, but that’s an old machine.

Just for fun, I ran the same build on the PineBook Pro (which runs Manjaro KDE): Total time: 21:27 min. Of course, that’s not usable for intensive development 😉

Finding a type in the classpath of an Eclipse Java project

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Recently, I started to contribute and maintain Pitclipse, an Eclipse plugin for running mutation testing with PIT.

We needed a mechanism to detect whether JUnit 5 is in the classpath of a Java project (so that we could run PIT with its JUnit 5 plugin).

The first implementation of such a mechanism was rather cumbersome since it manually inspected the Java project’s classpath entries. Something like that:

That’s rather unclear, and there are lots of paths to test.

I opened an issue for investigating an alternative implementation, https://github.com/pitest/pitclipse/issues/149, and I was thinking of something simpler, along these lines:

We could try to load some classes of the JUnit 5 engine by constructing a classloader using the classpath of the Java project.
Something like (untested):


That’s simpler and cleaner, but we can do better than that 🙂

JDT provides a lot of API for such things. For what we need to do, we can simply rely on IJavaProject method findType:

IType findType(String fullyQualifiedName)
Returns the first type (excluding secondary types) found following this project’s classpath with the given fully qualified name or null if none is found.

So it’s just a matter of creating a reusable method, e.g.,

And we can simply call it by specifying the fully qualified name of a type that we know belongs to JUnit 5 (PR https://github.com/pitest/pitclipse/pull/199):

Now we don’t even have to test several cases: we simply rely on the correctness of the implementation of findType. This is expected to work on Java projects, Maven projects, Gradle projects, etc.

My notes on the Grub incident in Linux Arch

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In this post, I’d like to share my thoughts and the solution I adopted to circumvent the terrible incident that happened a few days ago with grub in Linux Arch. The bug affected all Arch-based distributions (not Manjaro, which is not really Arch-based, but for sure EndeavourOS and Arch itself).

You can find the details of the problem online:

If you’re reading this, you’re already aware of the bug, and maybe you’ve been hit by it. Thus, I’m not going into the details of the issue itself.

First of all, although I’ve been enjoying Arch for some time, I must say I was not pleased with the way the Arch team handled the problem (it’s really a severe issue, and having bootable snapshots does not save you from that if you don’t take countermeasures to avoid it or to fix the problem, once you’ve already been hit). After a few days, the Arch team closed the bug, blaming other Arch-based distros because they have hooks that update the grub configuration during package upgrades. The Arch team says that if you use grub the “Arch way,” you have no problem. However, if I understand the details of the issue correctly, as soon as you have a software update that installs a new kernel version, it will also update the grub configuration, and the bug will hit you. (update: no, that’s not the case in Arch, since the kernel image file always has the same name and does not have the version in the name).

Moreover, I have hooks to take Timeshift snapshots before a system upgrade and to generate grub entries to boot the snapshots. Isn’t this the “Arch way”? For sure, it’s a safety mechanism widely adopted. After all, Linux is about choice! 🙂 (update: since, as said above, the kernel image file name is always the same, even, for example, if you update from version 5.19.4 to 5.19.5, having bootable snapshots is even more crucial in Arch).

The issue is said to be fixed by showing a warning during the upgrade of the grub package saying:

Seriously?! That’s just a warning, which is likely to go unnoticed. That’s not a fix; it’s a patch (In the true sense of the word).

However, let’s say that you note that warning and do what it says.

You will have no problem on the next boot, but I found these huge drawbacks (at least for me):

  • The grub installation of the current Arch distribution will replace the default UEFI boot configuration. Of course, you can reorder the boot configurations from the UEFI setup, but that’s an unwanted side-effect if you had already configured things the way you wanted;
  • Related to the previous point, if you have another grub configuration (e.g., of another distro) to boot other distros on the same machine (see, e.g., my blog post on this mechanism), including this Arch installation, it will not work anymore. That’s expected because the other grub does not know anything about the new grub configuration anyway.

Moreover, in my humble opinion, what the grub developers have done in this new version does not make much sense: why do you want to execute a command to generate a boot entry dynamically?! Perform that choice when generating the grub configuration once and for all!

If you’re curious, that’s the difference after the grub update in the file used to generate the culprit entry in the grub.cfg (old file on the left, new file on the right):

So, after restoring my computer with arch-chroot (because I was hit by the bug), instead of their proposed “solution,” I ignored the package update by adding this line to /etc/pacman.conf:

This way, I won’t be hit by the bug again (until, hopefully, grub developers will revert that implementation decision, and Arch developers will provide a new grub package)

Then, I realized that, in the end, I don’t need a grub entry to enter UEFI! I can enter UEFI when starting the computer with a key combination (not to mention that, as I said above, my main grub is not the Arch one, but the Fedora one, as shown in my blog post)! Thus, I updated the grub package (of course, after removing the IgnorePkg entry shown above). Before rebooting (that’s crucial), instead of following the suggestion shown during the upgrade, I simply removed the grub file to generate the culprit configuration for UEFI in the grub.cfg (and, of course, I regenerated the grub configuration afterward):

That’s all! Your grub.cfg will not have an entry for entering UEFI anymore. I don’t need that.

Of course, you have to repeat these operations if Arch releases an update to the grub package without fixing the problem. However, I prefer this solution, which does not have the abovementioned drawbacks.

A first look at Crystal Linux

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Crystal Linux is a brand new Linux distro based on Arch. Although it has not been officially released, you can already download an ISO and try that in its current development state.

Quoting from its home page:

Crystal Linux is a brand new Arch Linux based distribution.
Powerful and easy to use.

And, in particular

Why Crystal?
What’s so different about Crystal compared to other distributions?

  • Easy to use package manager
  • Beginner Friendly
  • Easy Btrfs snapshots
  • Easy to install

Since I’ve been using Arch and Arch-based (mainly EndeavourOS) distros for a while, I decided to try it, even if it’s not officially released, to briefly evaluate its current development status.

I downloaded the ISO crystal-live-08-20-22-07-55-x86_64.iso and tested it on a VirtualBox VM.

After the BOOT, you’re greeted by the GNOME desktop. I searched for the installer. I thought I’d find it in the dock, but that was not the case. I searched for an “install” string in the GNOME Activities. Again I got no results. Then, I recalled that Crystal names its installer Jade, and that’s how I found it.

The installer provides several screens to specify the typical information of a Linux installation. I would say that it does that in a very clear way. Here are a few screenshots of the pages of the installer:

Since it’s based on Arch, Crystal can provide a good selection of desktop environments. However, you can select only one:

Another interesting section is the next one, where you can enable Timeshift (recall from the introduction that “Easy Btrfs snapshots” is one of the advertised features):

Regarding partitioning, the Crystal Linux installer shows its “work-in-progress” state: you can only select the disk for the installation and nothing else. As noted in the dialog, it will wipe the whole disk and automatically partition it. Nothing is said about the file system, but I guess it will be a Btrfs filesystem (Spoiler: it is):

However, they are still working on the partitioning program:

Then, you get the summary for a final review. When you’re ready, start the installation:

The installer shows the installation log, which is excellent and helpful. Unfortunately, when the installation finishes, the log is not available anymore. It would be good to have access to that window still, to copy the log somewhere for a later examination.

OK, let’s reboot and see the distribution in action.

Crystal Linux should come with a customized GNOME desktop, Onyx, but that’s not installed by default. So you get a vanilla GNOME session (just like in Arch) with only a few programs installed (so, in this respect, it’s not bloated):

You don’t even have a Text Editor with a GUI (but at least you have Gnome Tweaks):

Of course, you can install whatever you want with pacman or with the Crystal custom AUR helper, amethyst, but beware: the command to run it’s ame; it took me some time to discover that 🙂 The AUR helper amethyst looks nice. Just like “yay”, you run it, and it also executes an update (“-Syu”). Besides that, the command line arguments are the same as pacman and yay, at least, that’s my first impression. Just like yay, amethyst also updates the AUR packages. Moreover, it is also configured to execute “pacdiff” at the end:

Unfortunately, the keyboard layout and the time zone I specified during the installation was not considered. I had to set them again in the GNOME settings.

The default shell is ZSH, which I like. However, it’s not configured at all, with any default. Thus, the first time you open a terminal, you have to do that yourself:

Let’s see how the installer created the partitions:

So we have BTRFS, with the two standard volumes @ and @home, which are suitable for Timeshift. No SWAP partition (swap is not configured at all). Moreover, there’s no compression on the BTRFS subvolumes, while I usually prefer to have compression.

There are also other subvolumes (I guess to exclude from snapshots the virtual machines you might create with Kvm):

Concerning repositories, Crystal is similar to EndeavourOS: it relies on Arch repositories and adds just a few custom repositories that you can also browse at https://repo.getcryst.al/. You can see that there are not so many packages there. Besides the Crystal programs, you also find a few packages you typically install from AUR, like timeshift and timeshift-autosnap.

This allows me to talk about the “Easy Btrfs snapshots.” The Crystal installer has already set up timeshift, timeshift-autosnap (which creates snapshots before package upgrade), and grub-btrfs (which adds “btrfs snapshots” to the grub menu to boot your system on a “snapshot” from the grub menu). (I wrote about these 3 tools previously).

For example, that’s what you see when you perform an upgrade (note the automatic creation of the snapshot and the creation of the grub menus for the snapshot):

In fact, the next time you boot, you also get the grub entry for the snapshots:

Summary

I liked a few things and a few things I did not like, but I enjoyed the installation, and, in general, I have an excellent impression of this new distribution. It’s not for beginners, but it’s easy for users who have already tried a few Linux distributions.

In any case, I found Crystal promising, and I really look forward to the official ISO release!

Ubuntu Jammy and Nvidia

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I installed Ubuntu Jammy a few months ago, when it was released, on a desktop computer. It was a terrible experience: crashes now and then, and the Wayland session was not working well on some applications. After a week, I uninstalled it immediately and switched to Fedora on that computer.

Then, a new point release came out, 22.04.1. I heard that, in the meantime, many bugs were fixed. I decided to give it another chance. In particular, I decided to install that on an older computer, a Dell m3800, because it comes with an integrated video card and a “terrible” Nvidia card, which is well-known to give headaches to Linux users 😉 In the past, I used Bumblebee on such a computer to keep the power consumption low. However, Bumblebee gave me problems in the past, and I seem to understand that it is not actively maintained anymore. So, let’s try a fresh installation of Ubuntu Jammy and see how it deals with the Nvidia card.

The installation went fine and smoothly. In the end, when rebooting into the new installation, I could verify that the Nvidia drivers were installed automatically and working correctly (meaning no crashes or other issues)!

Since it uses Nvidia, Ubuntu does not show any gear icon on the login screen to switch the graphical session: it’s X11 automatically, and you cannot change it. I guess that’s done because Nvidia does not work correctly in a Wayland session.

Another nice thing is that it detected my huge screen resolution, 3200×1800, and automatically enabled 200% scaling. However, I seem to remember that this is a feature of Gnome itself.

Having said that, I found using the Nvidia drivers really a problem: the computer gets immediately hot, the fans get pretty noisy, and it looks like the battery does not entirely charge even when connected to the AC. It also looks like the battery goes down a bit, even when connected to the AC.

I opened the Nvidia settings. However, it looks like Hybrid mode will not work with this version of the driver.

Of course, when running on battery, the power consumption is too much, and the battery would drain in less than two hours, as reported by powertop. That’s the reported consumption (even when the computer is idle):

33.6 W of power consumption is too much.

Since I’m not using graphical intensive software, I tried to switch to the integrated Intel graphics card. You cannot select this choice in the Nvidia settings because it’s greyed out (you can find many posts on the Internet reporting this problem without a solution). However, we can use the command line:

Let’s reboot, and now the gear icon appears, and you can select the Wayland session since the Nvidia card is not used. By the way, Nvidia settings still have the greyed-out entry for the integrated card, but at least it recognized that’s the one selected:

The power consumption on battery is better (about 15 W, i.e., half), but I seem to understand that the Nvidia card itself it’s still using power since it’s not completely turned off:

At least the computer is not that hot anymore, and the battery seems to charge correctly.

Let’s try to use a tool to turn the Nvidia card off: EnvyControl.

Let’s install that:

As noted here, there are a few additional steps when installing EnvyControl in Ubuntu:

We could use the envycontrol command to set the card, but let’s now install a Gnome extension with a GUI for the switch: GPU profile selector.

Let’s also activate the extension.

Let’s reboot, and now, in the Gnome dropdown menu about the battery and power profile, we also have the menu entries to select the card:

Remember that we had to set the “on-demand” mode for installing EnvyControl. That’s why the “Hybrid” entry is selected.

Let’s select “Integrated” and reboot; now, the Nvidia card should be off.

The power consumption on battery is even better now (13.8 W):

If we switch to the Wayland session, it even improves a bit:

I find this installation usable, and I saw no issues for the moment.

That’s all for now!

Cropping images with KDE Gwenview

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I’ve always been using GIMP for cropping images (for articles, books, etc.), and it works pretty well, but I never thought that you could do the same much quicker with the default image viewer of KDE, Gwenview. In KDE Plasma, I’ve always used Gwenview as an image viewer, but it’s much more:

Gwenview is a fast and easy to use image viewer by KDE, ideal for browsing and displaying a collection of images.

Features:

  • Supports simple image manipulations: rotate, mirror, flip, and resize
  • Supports basic file management actions such as copy, move, delete, and others
  • …

In fact, you just open an image with Gwenview:

Press “Show Editing Tools” and then select “Crop” from the palette:

The box for cropping is ready to be resized:

When you’re done, just press ENTER:

and the image is ready to be saved!

With GIMP, the number of steps is much more significant.

Moreover, with Gwenview, once you cropped and saved the current image, you just press the right arrow to go to the next one. Much faster!

Installing Arch Linux with the archinstall script

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After using EndeavourOS for a while, I also decided to try Arch itself!

I did not feel ready to go through the manual procedure (but I’ll do that someday), and I heard about the archinstall script, which comes in the Arch official ISO. After watching a few videos and reading a few blog posts, I tried that myself, first on a VM and then on a real machine.

I can anticipate that I liked this installation procedure. Still, it is not perfectly usable in a multi-boot environment, as I’ll say near the end of this post, where I summarize my experience with the installation.

In this post, I’ll first show an installation on a VM (and I suggest you try that one), then briefly describe the installation on a real machine.

If you want to try that, you have to download an official Arch ISO. Once you booted into the live ISO, you must connect to the Internet as described in the official documentation.

Now, it’s time to run the installer:

And you have access to the main installation menu:

You see, it’s easy to use, especially if you’re familiar with other Linux installation programs.

The first three entries are easy to deal with.

The fourth, “Select harddrives,” requires some care because it’s where you deal with your disk! You have to select the correct drive. In my case:

Since I’m on a VM, I’ll simply choose to wipe everything on that drive and let the installer handle the partitioning automatically. That’s easy in a VM, and that’s what I’ve seen in all demos on the web (but, as I’ll show later, things are more complicated in a multi-boot environment):

Then, you choose the filesystem EXT4, BTRFS, etc.

For the bootloader, I chose GRUB, which is the one I’ve always used.

Concerning the user accounts, it’s best NOT to set a root password: it’s better to create a user with administrator rights (so that you later rely on the good ol’ “sudo”). An interesting feature of this installation procedure is that it lets you create as many users as possible. On the contrary, typically, other Linux installations only allow you to create a single user.

The other interesting menu entry is the one to choose the profile. I’m choosing “desktop”:

And in particular, I’m choosing GNOME (you see that you have plenty of choices):

Moreover, you can select the graphic drivers:

And the kernels:

Since, for the moment, you could just select from a predefined set of choices, you are given a chance to manually specify additional packages to install (but you have to know them by their name). In this example, I’m installing “firefox”:

It’s also crucial to configure the network for the installed system. If you use GNOME or KDE, I’d say that it’s best to choose “NetworkManager”:

Once you’ve done with all the menu entries, before starting the actual installation, you’re given a chance to save these configurations, which is helpful if you want to use the same configurations on other machines or to do some further customizations:

Now, it’s time to choose “Install”; a countdown starts to abort the installation in case you just remembered you’ve done something wrong:

The installation starts and in a few minutes (where a few packages will be downloaded)…

…you should get to the end of the installation, where, if you want, you can also tweak the installed system before rebooting:

If you choose “no”, you’re back to the live environment:

And you can now reboot to (hopefully) enjoy your installation:

Having installed GNOME, I’m presented with a few options, and I choose the first one, that is, GNOME on Wayland:

You see that the GNOME installation is a vanilla one.

OK, that was a VM, and it was straightforward to install Arch with the installation script. It’s also easy if you plan to install ONLY Arch on your computer (by wiping all the rest).

Things are not working completely fine if you want to install it on a computer with other Linux installations, which you want to keep and be able to boot into. In this case, of course, you cannot wipe the selected hard drive and must do manual partitioning. The installation script is still helpful in that respect (I’m not showing anything in this blog post), but you must be aware of a small problem.

In fact, due to an issue, which, at the time of writing, is still open, specifying to mount an existing EFI partition into “/boot/efi“, which, as far as I know, it’s the standard mount point in most distributions (every distribution I know at least). You must specify a mount point “/boot” and that must be a boot partition (with the boot flag). Of course, that’s what I’ve done myself; I specified the exiting EFI partition (the first partition of the installation drive in my computer) for the mount point “/boot”. However, the installer will treat that directory as if it was /boot/efi in other installations. Thus, it will copy the booting files directly there. As a sad result, the Arch installation will not be detected when rebooted. You will only see an existing installation’s GRUB menu (and running os-prober from an existing installation does not seem to help). Thus, you end up with the Arch installation that you cannot boot.

The only solution I found to boot into the Arch system was to apply the mechanisms shown in my other post and configure the Fedora GRUB with an entry pointing directly to the EFI partition, i.e., according to the post mentioned above, something like the following (remember, on my computer the EFI partition is the first one, and I installed Arch on the partition 13):

Or even like that (i.e., without specifying the root partition of the Arch installation at all and just relying on the grub that the installer created directly on the EFI partition):

Besides this problem, the installation script archinstall is really interesting and still under development.

Locate and BTRFS

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I’ve always been using the locate command (provided by the mlocate package or by the new plocate package), which quickly searches for files and directories by their names. The command relies on the database built by the command updatedb (which should be run periodically, e.g., by enabling the plocate-updatedb.timer service for plocate).

Unfortunately, by default, it does go well with the BTRFS filesystem and its subvolumes (see, e.g., this bug), resulting in empty results for all searches basically.

Fortunately, the solution is quite simple:

  1. edit the file /etc/updatedb.conf
  2. replace PRUNE_BIND_MOUNTS = “yes” with PRUNE_BIND_MOUNTS = “no”
  3. save, exit and re-run updatedb

Then, you can enjoy locate’s search results 🙂

Linux EndeavourOS Artemis Review

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I have already blogged about EndeavourOS, which I use most of the time on a few laptops. Since EndeavourOS, based on Arch, is a rolling release, I update it almost daily and don’t need to install it from scratch when a new release comes out, like Artemis, which was released a few days ago. However, since I wanted to switch from the EXT4 file system to BTRFS (since I started to experiment with this file system and its snapshot capabilities), I took the chance to try this new release by installing it from scratch (of course, using BTRFS this time).

I’ll first go through the installation, but I can anticipate that, once again, I’m impressed by EndeavourOS. This installation feels really fast, maybe due to BTRFS or the new kernel (instead of the LTS kernel, I now use the latest one provided by the distribution) or both. Most of all, EndeavourOS is pure Arch but with outstanding defaults. Indeed, the KDE and GNOME environments are vanilla ones.

Installation

As usual, the first thing to do, once booted in the live environment, which in this case is XFCE, is set up the network connection. You might also want to change the keyboard layout (Disable system defaults and install your layout, in my case, it’s the Italian layout):

Then, let’s update the mirrors (typically by selecting your state) and start the installer.

I choose the “Online” method because I want to install KDE Plasma instead of Xfce.

You have to wait a few seconds (or about a minute) for the installer to download the modules (I always prefer to install any operating systems in English):

Maybe, due to a bug, the location has been found successfully, but the English version proposed is not the right one, so I have to change it to Americ English again:

After setting the keyboard layout (this time for the installed system), it’s time for partitioning.

Since on this computer I have a few Linux installations, including the old version of EndeavourOS I’m going to replace, I choose Manual partitioning (and not “Replace a partition” because that would keep the same file system type, EXT4, while I want to switch to BTRFS).

I Edit the partition, select “Format” (otherwise, I cannot change the File system type), modify the File system (BTRFS), and specify the mount point.

Before going on, we must specify to mount the EFI partition (into /boot/efi) without formatting it and ensure the “boot” flag is selected. This way, the installer can properly install GRUB.

WARNING: on another computer, the installer complained that I did not select a boot partition with at least 300Mb (mine was just 200Mb). Since I knew there was enough space in that partition, I ignored the warning, and the installation went fine.

As for the desktop, I select Plasma.

And then, we can select the single packages. Note that, different from my previous review, you choose the packages after selecting the desktop, so that a few packages, in particular, the ones of the chosen desktop, have already been selected:

In this blog post, I’m not going to install GNOME besides KDE, but I also select the “Printing-Support” and the “Support for HP Printer/Scanner” checkboxes.

As usual, then you have to specify your user’s details, and then it’s time to take a look at the summary:

Let’s start the installation. It might take a few minutes because it’s an “Online” installation, so it has to download several packages.

You can press “Toggle log” during the installation to see the installer’s log.

When it’s done, it’s time to restart the computer.

First impressions

As in the previous blog post, I must note that the Discover icon is still in the taskbar, though the software manager Discover is not installed at all.

Maybe because I selected KDE Plasma only, the Wayland session has not been installed, while in my previous post, I installed both GNOME and KDE. However, I just had to run this command:

And then I could enjoy Plasma also in Wayland, which seems to be pretty usable.

A nice addition is a firewall applet in the taskbar

Here’s neofetch:

Printing support is excellent! I connected an old USB HP Deskjet printer, and I got these notifications from Plasma:

The printer has been automatically installed correctly (I only had to configure a few things like paper size and color mode).

Setting up my Google accounts (drive access and calendar) is as cumbersome as always, but I did not experience any problems once I finished.

Power consumption on the battery is also excellent, but that was true in the past, so nothing changed in that respect.

All in all, this distribution keeps on being awesome.

As I initially anticipated, you have Arch and its vanilla desktop environments, but with useful and reasonable defaults. Moreover, the installation is effortless! 🙂

Enabling Hibernation in Arch-based distros

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I had already posted about enabling hibernation in Linux, particularly in Ubuntu.

Thanks to the script hibernator, the procedure is much more straightforward in Arch-based distros (including Manjaro and EndeavourOS).

First of all, make sure you first install the package update-grub.

The package hibernator is available from AUR, but currently, there’s a problem with the build instructions. Thus, we must install it manually. There’s no need to install the script anywhere: it’s just a matter of cloning the script from GitHub and running it once:

Then, before running the script (as a superuser), we must decide where we want the suspend-to-disk to take place: either in a swap partition or in a swap file (please keep in mind that currently, the script cannot handle hibernation into a swap file of a BTRFS partition).

If we want a swap file, the script can create that for us, and we can also specify the size of the swap file. Here’s the quote from the home page of the project

Hibernator accepts desired size of swapfile as arguments. Running hibernator 2G creates 2 Gb swapfil, hibernator 1000M creates 1000 Mb swapfile. The script defaults to 4G if no arguments are given.

If we want a swap partition, we must ensure the partition is already in place and that our /etc/fstab already refers to that (i.e., it mounts it appropriately).

When we’re ready, we just run the script with sudo. The script will update the GRUB command line with the resume option and a resume hook to /etc/mkinitcpio.conf. Finally, it will update the GRUB configuration (with update-grub, that is why you need to install this package beforehand).

Here’s an example of the output:

And that’s all: we just reboot, and hibernation is ready to be used!

Before rebooting, you might want to check that the GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub has been set with a valid resume entry (if you rely on a swap partition, which has been properly specified in /etc/fstab, it should contain a reference to the UUID of the swap partition):

You can test that, as usual, with

You may also want to refer to the older post enabling hibernation in Linux, particularly in Ubuntu, for other mechanisms related to hibernation, like suspend and then hibernate.

Timeshift and grub-btrfs in Linux Arch

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UPDATED 02/Jan/2023, ChangeLog:

  • 02/Jan/2023: documented that the new version of grub-btrfs is now an official package (you still have to install another package: inotify-tools);
  • 02/Dec/2022: documented the new version of grub-btrfs and its new grub-btrfsd daemon; the configuration for Timeshift is much simpler, but you have to install another package: inotify-tools.

After looking at the very nice videos of Stephen’s Tech Talks, in particular, this one https://www.youtube.com/watch?v=6wUtRkEWBwE, I decided to try to set up Timeshift, Timeshift-autosnap, and grub-btrfs in my Linux Arch installation, where I’m using BTRFS as the filesystem. These three packages allow a timeshift snapshot to be automatically created each time you update your system; moreover, a new grub entry is automatically generated to boot into a specific snapshot.

The video mentioned above is handy, but unfortunately, some recent changes in Timeshift itself broke the behavior of the two other packages. In this post, I’ll try to show how to fix the problem and go back to a working behavior. I’ll also show an experiment using the snapshots so that, hopefully, it’s clear what’s going on in the presence of such snapshots and how to use them in case you want to revert your system.

Install timeshift and timeshift-autosnap

First of all, let’s install timeshift and timeshift-autosnap (the latter depends on the former, and they are both available from AUR; I’m using the yay AUR helper here):

The programs will be installed from sources; thus, they will be compiled (it might take some time).

Let’s create a new Timeshift snapshot to make sure it works (the first time, you will have to configure Timeshift; of course, it is crucial that you choose “BTRFS”).

You can configure timeshift-autosnap with the number of snapshots to keep (in this example, I specify 10):

Install grub-btrfs (new version, installation from the official repository, 02/Jan/2023)

The new version of grub-btrfs is now available as an official package (Please remove the old AUR version if you still have it installed):

So you can simply install it with pacman:

Now, let’s make sure grub-btrfs can find Timeshift’s snapshots (remember, we’ve just created one). So let’s update the grub configuration, and we should see in the end something like the following output:

The last lines prove that grub-btrfs can detect snapshots.

We now need to configure that to monitor the Timeshift snapshot directory instead of the default one (/.snapshots).

Automatically update the grub menu upon snapshot creation or deletion (2 December 2022)

What follows is based on the new version of grub-btrfs. At the bottom of the post, there are still the old instructions, which are to be considered stale and left there only for “historical reasons”.

Grub-btrfs provides a daemon watching the snapshot directory and updates the grub menu automatically every time a snapshot is created or deleted.

Important: This daemon requires an additional package:

By default, this daemon watches the directory “/.snapshots” (the default directory for Snapper). Since Timeshift uses a different directory, we have to tweak the configuration for the daemon.

Let’s run:

We must change the line

into

This is required for Timeshift version 22.06 and later because Timeshift creates a new directory named after their process ID in /run/timeshift every time they are started. Since the PID will be different every time, also the directory will be different. Grub-btrfs provides the command line argument –timeshift-auto to correctly detect the current snapshot directory (In previous versions of grub-btrfs, we had to tweak /etc/fstab to deal with that, as shown later in the old section).

Let’s start the daemon:

In the journalctl log, we should see something like (where the date and time have been stripped off):

Let’s start Timeshift. In the journalctl log, we should see something like this:

Let’s verify that if we create a new snapshot, grub-btrfs automatically updates the GRUB menu: in a terminal window, run “journalctl -f” to look at the log, then create a new snapshot in Timeshift. In the log, you should see something like the following lines:

Similarly, if we delete an existing snapshot, we should see something similar in the log.

Remember that it takes a few seconds for grub-btrfs to recreate the grub menu.

Once we’re sure everything works, we can enable the daemon to always start at boot:

The next time we boot, our grub menu will also show a submenu to boot snapshots.

Concerning doing some experiments booting a snapshot and restoring it, please look at the next section.

IMPORTANT: If you have several Linux distributions on your computer and you use a multiboot system like the one I blogged about, and this distribution is not the main one, you will have to manually tweak the entry in your main distribution’s GRUB menu. See the linked blog post near the end.

Some experiments

Let’s do some experiments with this configuration.

Here’s the kernel I’m currently running:

I’m updating the system (I’m skipping some output below, and you can ignore the “stale mount” errors):

So it created a snapshot before updating the system (in particular, it installed a new kernel version). Let’s reboot and verify we are running the new kernel (5.18.8 instead of 5.18.7):

Let’s reboot and select from GRUB the latest snapshot (remember, the one before applying the upgrade), so timeshift-btrfs/snapshots/2022-07-02_15-35-53 (snapshots are presented in the grub submenu from the most recent to the oldest one). We do that by pretending that the update broke the system (it’s not the case), and we want to get back to a working system before the update we have just performed.

You see that the “Authentication Required” dialog greets us, and in the background, you can see the notification that we “booted into Timeshift Snapshot, please restore the snapshot”:

The password is required because it’s trying to run Timeshift:

In the screenshot, you can see that we are now using the older kernel since we booted in that snapshot, where the update has not yet been performed. We have to restore the snapshot manually; otherwise, on the next boot, we’ll get back to the updated system version and not in the snapshot anymore.

So, let’s restore the snapshot:

You see, Timeshift has created another snapshot ([LIVE]). We now reboot normally (that is, using the main grub entry, NOT the snapshot entries).

Once rebooted normally, we can verify again that we are running the old kernel:

Let’s have a look at Timeshift, and we can see the last snapshot is an effective one, not a LIVE one:

Yes, we are now in a system where the update above has never been applied.

Let’s try to rerun the update command (we don’t effectively execute the update, it’s just an experiment):

Why? Because the snapshot had been created automatically by timeshift-autosnap before applying the updates while the package manager was running, its lock is still there.

Let’s remove the lock and try to rerun the update:

The output is similar to the one shown above (unless there are even more new updates in the meantime, which might happen in a rolling release), but something is missing:

Why? Because the downloaded packages in the cache are NOT part of the saved snapshot, they are still present in the current system, even though we restored the snapshot. Why are the cached packages still there, but the lock has been restored with the snapshot? That’s due to the way subvolumes are specified in the /etc/fstab:

You see, the cache of downloaded packages and the logs are NOT part of the snapshots, while /var/lib (including the pacman lock) is part of the snapshots.

Let’s now revert the snapshot: we select the one with “Before restoring…”.

Again, we are now in a LIVE situation, and Timeshift tells us again to reboot to make it effective.

Let’s reboot (by using the main grub entry).

We’re back to the updated system, and there’s nothing to update (again, unless new updates have been made available in the meantime):

If we’re happy with the updated system, we can also remove those two snapshots (remember that grub-btrfs monitors the snapshots so that it will update its grub submenu entries):

I hope you find this blog post helpful, and I hope it complements the beautiful video of Stephen’s Tech Talks mentioned above.

Old version (with old release 4.11 of grub-btrfs)

UPDATE 02/Dec/2022: These are the older instructions for the previous version of grub-btrfs, where there was no “grub-btrfsd.service” and there was another systemd program (“grub-btrfs.path”).

I leave these instructions here just for “historical reasons”.

The first problem is that timeshift has recently changed the strategy for creating snapshots. Instead of creating them in /run/timeshift/backup/timeshift-btrfs/snapshots, it now creates them in /run/timeshift/<PID>/backup/timeshift-btrfs/snapshots, where <PID> is the PID of the Timeshift process. Each time you run Timeshift, the directory will be different, breaking grub-btrfs (which expects to find the snapshots always in the same directory).

Fortunately, there’s a workaround: we add an entry to /etc/fstab in order to mount explicitly the path /run/timeshift/backup/timeshift-btrfs/snapshots:

where, of course, <UUID> has to be replaced with the same UUID of the physical disk partition.

Reboot, and then Timeshift will also put the snapshot in that directory (besides the one with the PID, as mentioned above). You can try to create a snapshot to verify that (this also allows us to use the Timeshift wizard so that we specify to create BTRFS snapshots).

Let’s make sure the mount point is active (and note the unit name)

Let’s now install grub-btrfs

We need to configure that to monitor the Timeshift snapshot directory instead of the default one (/.snapshots).

The file contents

should be replaced with

Let’s reload and re-enable the monitoring service:

If we have already created a few snapshots, we can run update-grub (or, if you have not installed the package update-grub, use the command “grub-mkconfig -o /boot/grub/grub.cfg”) and verify that new grub entries are created for the found snapshots:

We can also restart the system and prove that we can access the GRUB submenu with the generated entries for the snapshots.

KDE Plasma 5.25 in Arch

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After the recent release of KDE Plasma 5.25, this version landed a few days ago in Arch-based distros like EndeavourOS (the one I’m writing from).

Although I’m mostly a GNOME user, I also have a few distributions installed where I’m using KDE Plasma.

The new features that impressed me most are related to eye candies 🙂

First, the “Present Windows” effect now looks the same as the new “Overview” effect. If we compare the “Present Windows” effect in the previous version (5.24):

with the new one:

we can see a significant improvement: in the earlier versions, the windows not selected were too dark, making it hard to distinguish them. This behavior relates to an old bug (10 years old): https://bugs.kde.org/show_bug.cgi?id=303438. This bug has been fixed by rewriting this effect “to use the same modern, maintainable backend technology found in the Overview effect.”

I use this effect a lot (I also configured the “Super” key to use this effect, simulating what happens in Gnome for its “Activities” view), and I use the filter to filter the open windows quickly. So I appreciate this usability change a lot!

One detail I do not like in this new version of “Present Windows” is that the filter textbox remembers the entered text. Thus, the next time you use it, the presented windows are already filtered according to the previously entered text. I’m not sure I like this.

The other cool thing introduced is the automatic accent color! Accent colors were introduced a few versions ago in Plasma, but now you can have Plasma automatically adjust the accent color from the current wallpaper:

If you use a wallpaper changer mechanism (like the one provided by Plasma), possibly by downloading new wallpapers (like Variety), you will get nice accent colors during the day. Here are a few examples produced running Variety to change the wallpaper:

Maybe it’s not an important feature, but, as we say in Italy, “Anche l’occhio vuole la sua parte” 😉

The last new feature that positively impressed me is that now KRunner also shows Java files (and probably other programming languages related files) when you search a string. Previously, although “Baloo” (the file indexing and file search framework for KDE) knew about these files, KRunner was only showing .txt files and a few others, but not Java files.

Concerning Wayland, one thing I noted is that if I start a Plasma Wayland session using a brand new user, it automatically scales the display in case of an HDPI screen. Wayland usability in Plasma has not improved since my last experiments (see KDE Plasma and Wayland: usability).

 

Xtext 2.27.0: update your Xbase compiler tests

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If you update to Xtext 2.27.0 and have compiler tests for your Xbase DSL that assert the output of the compilation, you’ll get lots of failures after the update.

I am guilty of that 😉
Well, for a good reason, at least 🙂

In fact, I worked on this issue: https://github.com/eclipse/xtext-extras/issues/772 and its fix is included in Xtext 2.27.0.

Now, the Xbase compilation mechanism does not generate useless empty lines anymore (before, it added lines with two spaces). Your compiler tests will fail because the output is different.

I personally fixed my tests in my DSLs by simply using the Find/Replace mechanism of Eclipse with this substitution pattern (there are two space characters between the tab character and the newline character):

If you have deep nesting in your compilation output, you might have to repeat this substitution with more than two characters, but this should not be required unless you generate nested classes or something like that.

With the above substitution a test like the following one:

will become like the following one (you see the difference: no empty line with two characters between the two generated constructors:

Now your tests should be fixed 🙂

Configure Arch Pacman

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Pacman is the package manager in Linux Arch and Linux Arch-based distributions.

I’ve been using EndeavourOS for some time, and I enjoy it. EndeavourOS is pretty close to vanilla Arch. I also experimented with pure Arch (more on that in future blog posts). However, the output of pacman in EndeavourOS is much more excellent and “eye candy” than in Arch. However, it’s just a matter of configuring /etc/pacman.conf a bit in Arch to have the “eye candy” output.

These are the options to enable in the [options] section in that file (the ParallelDownloads does not have to with the output, but it’s a nice optimization):

Without these options, this is the output of pacman (e.g., during an upgrade):

And this is the output with the options above enabled:

Besides the colors, you can spot c’s for the progress representing “Pacman,” the video-game character, eating candies (that’s the aim of the option ILoveCandy)… waka waka waka!  🙂

The colors are also helpful when searching for packages:

Happy Pacman! 🙂

macOS: switch between different windows of the same application

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Maybe this is well-known to macOS users, but it wasn’t clear to me as a Linux user.

As a Linux user, I’m used to using Alt+Tab to switch between different windows. But I also use the shortcut to switch between different windows of the same application. In Gnome, the shortcut is Alt+<the key above Tab>, which is cool because it works with any keyboard layout. In KDE it is Alt+backtick (`), which has to be changed in Italian keyboards, like mine to Alt+\. Indeed, in the Italian keyboard layout, the key over tab is \.

In macOS it’s the same as in KDE: the shortcut is bound by default to ⌘+`, which of course it’s unusable in Italian keyboards (you should use a complex combination of keys only to insert the backtick ` character). You then have to configure the shortcut “Move focus to next window”, which is quite counterintuitive to me (I had always thought that it wasn’t possible in macOS to switch between windows of the same application if not by using the touchpad gesture or by pressing the down key after using the standard switcher):

Change it to something suitable for your keyboard layout. For the Italian layout I change it to ⌘+\:

And then you’re good to go! 🙂