Here is an error I've seen several times before, but I didn't find the time to troubleshoot until now:

	$ flatpak install --user flathub im.pidgin.Pidgin
	Looking for matches…
	error: No remote refs found similar to ‘flathub’
	

It has an easy fix:

	$ flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo 

	$ flatpak search --user pidgin
	Name         Description                    Application ID         Version       Branch       Remotes
	Pidgin       Instant Messaging Client       im.pidgin.Pidgin       2.14.12       stable       flathub
	

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Although it took me a while to figure out what was failing here, I finally noticed. I recently switched my default GNOME theme to the Nordic Polar theme. It seemed to work for most applications, including Firefox. However, for whatever reason, it didn't work on a couple of Firefox profiles (I separate my work into multiple, distinct profiles). The trick was to open the Firefox preferences, and switch from whichever non-default theme I had been using to the "System theme". As soon as I did that, it immediately adopted the Nordic Polar theme from GNOME just fine. {link to this entry}

Ars Technica had an interesting article on the famous quote on regular expressions by Jamie Zawinski:

Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.

My favorite explanation of the quote is the one by user MichaelT:

Some programming technologies are not generally well-understood by programmers regular expressions, floating point, Perl, AWK, and others).

These can be amazingly powerful tools for solving the right set of problems. Regular expressions in particular are very useful for matching regular languages. And there is the crux of the problem: few people know how to describe a regular language (it's part of computer science theory/linguistics that uses funny symbols—you can read about it at Chomsky Hierarchy).

When dealing with these things, if you use them wrong it is unlikely that you've actually solved your original problem. Using a regular expression to match HTML (a far too common occurrence) will mean that you will miss edge cases. And now, you've still got the original problem that you didn't solve, and another subtle bug floating around that has been introduced by using the wrong solution.

This is not to say that regular expressions shouldn't be used, but rather that one should work to understand what the set of problems they can solve and can't solve and use them judiciously.

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I've been using the Telegram messenger software on Linux for a few years now. And, like many other people, it seems, the fact that the default client doesn't truly fit into Adwaita, the default GNOME design language and theme, sort of bothers me. From time to time, I search for an alternative. But, to this date, I had not found anything. Until today, that is. I installed the Paper Plane client, and it works nicely, at least so far. It uses Adwaita, so it integrates nicely with the GNOME environment. If anything, the only issue is that it is quite simple compared to the default client. But, as far as I can tell, it does what it's supposed to well enough. Here are the commands to install it from the Flatpak Beta repo:

	# flatpak remote-add --if-not-exists flathub-beta https://flathub.org/beta-repo/flathub-beta.flatpakrepo

	# flatpak install flathub-beta app.drey.PaperPlane
	

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Although I had been using Pocket from the days it was still known as Read It Later, I recently decided to try Omnivore instead. The main reason is that it is fully open source and, as far as I know, allows users to host the server side of things if they want. I haven't done that last bit yet and, as a matter of fact, when they start charging for keeping the content on their servers (they have not yet, but have announced that will do so, sooner or later), chances are I will pay for the service as a way to contribute to the development of the app. Said that, I like to have the option to self-host, shuld I ever decide that that is what makes sense for me. In any case, while running the Omnivore Firefox extension I recently ran into a problem where it failed to save the page and reported an error message:

	You have not granted the Omnivore extension consent to save pages.
	Check the extension options page to grant consent.
	

Yet, I'm pretty sure it was working fine a few days earlier. Not sure what changed. It may have been something on the browser side, or perhaps on the extension side. In any case, the fix is to right-click on the extension icon, select "Manage Extension", then click on the three dots, select "Preferences" and, finally, scroll down to the bottom of the page, and check the box for "I consent to data collection". That fixed it for me. {link to this entry}