Cobra's bits (Posts about desktop)

Ich glotz TV

Cobra — Sun, 29 Jan 2023 14:00:13 GMT

Well, actually I've essentially stopped watching linear TV about 20 years ago. My Loewe CRT TV set I'd bought in 1994 didn't take kindly to that and twice suffered from dried-up electrolyte capacitors. “You have to switch on the TV at least sometimes”, said the electronics guy who repaired the set. When it happened the third time, I didn't bother anymore, but lived without dedicated TV set for the next 5 years. My first flat-screen TV purchased in 2010 suffered the same fate when it all of a sudden developed dead pixel rows, resulting in a rapidly increasing number of black lines across the display.

It was not until 2018 when I finally gave in and bought a new TV set with the explicit purpose to enjoy the FIFA World Cup held this year. You all know that from a German perspective, this word cup was as much of a disaster as the following one in 2022. Regardless, the 65" QLED panel with three-sided ambilight is perfect for enjoying the occasional movie from my NAS or Amazon Prime Video.

This panel creates a high level of immersion due to its sheer size and the light surrounding it, providing a near cinematic experience for movies in FullHD and 4K resolution. For anything else the immersion may be a bit overwhelming, particularly if one is not willing to fully focus on the action displayed. For me, that's often the case when watching a football match, or a documentary on publicly broadcasted TV, and I would prefer to be able to watch the TV channel on my notebook with one eye while doing other stuff in the background.

Instead of a flull-fledged IPTV application such as hypnotix, I thought that a simple script may be more suitable to my needs. The script I've found on archlinux.de was basically just what I needed. I've merely integrated the download of the current URLs (done by a python script by Axel-Erfurt I've reproduced below), cleaned up a bit, and formatted it for zenity. I've also excluded some redundant channels to keep the list from cluttering.

#!/bin/bash

# Original livetv script by tuxnix and Mis,
# see `https://wiki.archlinux.de/title/Live-Tv <https://wiki.archlinux.de/title/Live-Tv>`_
# liveiptvstations.py by Axel-Erfurt,
# see `https://gist.github.com/Axel-Erfurt/5106f9bbef1fca1d63bb74a849607128 <https://gist.github.com/Axel-Erfurt/5106f9bbef1fca1d63bb74a849607128>`_
# Also see `https://wiki.ubuntuusers.de/Internet-TV/Stationen/ <https://wiki.ubuntuusers.de/Internet-TV/Stationen/>`_

script_path="$(dirname "$0")"
script_name="$(basename "$0")"

# Pull down a current list of IPTV channels
liveiptvstations.py > channellist.txt

# Basic formatting
sed -i -e 'N;s/:\n/ /' -e 's/^/FALSE /' channellist.txt
sed -i -e "s/ARD Alpha/ARD.alpha/" -e "s/ARD ONE/ARD.one/" -e "s/MDR Sachsen/MDR/" -e "s/BR Süd/BR/" -e "s/NDR Hamburg/NDR/" -e "s/RBB Berlin/RBB/" -e "s/SWR BW/SWR/" -e "s/WDR (Deutschland)/WDR/" channellist.txt

# Remove some redundant channels (optional, but beware they need formatting if included)
sed -i -e "/Tagesschau/d" -e "/ARTE.FR/d" -e "/ORF/d" -e "/Brandenburg/d" -e "/Anhalt/d" -e "/Thüringen/d" -e "/Mecklenburg-Vorpommern/d" -e "/Niedersachsen/d" -e "/Schleswig-Holstein/d" -e "/Lokalzeit/d" -e "/weltweit/d" -e "/BR Nord/d" -e "/SWR RP/d" channellist.txt

#create oneliner for zenity
channel_list=$(paste -s -d ' ' channellist.txt)

stream_url=$(zenity --list --title "Live IPTV channels" --text "Choose a channel:" --radiolist  --column "" --column "Channel" --column "URL" --print-column=3 $channel_list)

if(($? == 0)); then
        mpv "${stream_url}"
        exec "${script_path}/${script_name}"
else
        echo "Leaving LiveTV"
fi

#!/usr/bin/python
# -*- coding: utf-8 -*-
import requests
import json

# see https://gist.github.com/Axel-Erfurt/5106f9bbef1fca1d63bb74a849607128

url = "https://raw.githubusercontent.com/mediathekview/MServer/master/dist/live-streams.json"

data = requests.get(url).text

js = json.loads(data)

def parse_object_pairs(pairs):
        return pairs

decoder = json.JSONDecoder(object_pairs_hook=parse_object_pairs)
obj = decoder.decode(data)

for value in obj[2:]:
        print(f'{value[1][2].replace(" Livestream", "")}:\n{value[1][8]}')

Uptime

Cobra — Sun, 01 May 2022 13:41:26 GMT

This blog runs on a very affordable vServer hosted by netcup. For such low-end servers, no uptime guarantees are given by any hoster. Nevertheless, I always get mails whenever the server is down either for maintenance or because its temporarily out of order, and my feeling is that this happens only rarely. But just out of curiosity, I'd like to know what the actual uptime is.

A two page article in c't 26/2021 introduced me to uptime-kuma, which seemed to fit nicely what I was looking for. The only part I didn't like was the statement “Der einfachste und schnellste Weg Uptime-Kuma zu installieren, führt über Docker und Docker-Compose” followed by an installation procedure that I would call anything else then simple and fast. Fortunately, this statement applies only to the distributions favored by the c't. On Arch, the following two commands install and start uptime-kuma as a service:

yay -S uptime-kuma
systemctl enable --now uptime-kuma.service

After configuring the services to monitor and a day of collecting data, their uptime status is displayed on https://localhost/3001 as shown below for the web and IRC servers on pdes-net.org:

Too many meetings

Cobra — Sun, 13 Mar 2022 13:01:13 GMT

The number of meetings I'm requested to attend has increased by roughly a factor of five over the last two decades. Instead of five meetings per week I'm currently having five per day on average. It thus doesn't come as a surprise that I depend on an electronic calendar to organize and get reminded of all these appointments.

On my desktops, I'm using the integrated calendar of evolution since seven years. Over the time, this implementation of a PIM for the Gnome desktop has proven itself to be reliable and stable, in contrast to Kontact, its KDE counterpart I've tried to use before.

In any case, having a calendar on my desktops is not sufficient anymore, as future appointments are typically arranged after Zoom meetings that I usually attend with my notebook. And even that is not enough: I may want to check my appointments on a whim in the middle of the night, where only my smartphone is immediately accessible. In either case, I do not need a full-blown PIM, but just a calendar client synchronizing with both owncloud/nextcloud and zimbra.

On Linux/GTK, I thought that gnome-calendar would be the natural candidate with this functionality. To my surprise it's straightforward to add an owncloud/nextcloud account with the associated calendar, but zimbra is not part of the online account collection of Gnome, nor is a generic CalDAV server. I found that almost impossible to believe, but it's in fact a longstanding bug (eight years!) that has still to be acknowledged and addressed by the developers. Fortunately, there's a simple workaround: after installing evolution and adding the zimbra CalDAV server there, it also shows up in gnome-calendar. Apart from this issue, gnome-calendar delivers exactly what I wanted.

This entire affair is a whole lot easier on Android. Davx5 available on F-Droid provides a convenient backend for any number of CalDAV servers, and any calendar app will serve as frontend. It works just as well as gnome-calendar on my notebook, but without any unexpected obstacles during the configuration of the calendars.

I'm now reminded of outstanding appointments wherever I walk and talk. That's progess! Or is it?

Hidden settings

Cobra — Thu, 01 Apr 2021 07:34:07 GMT

Since I've quit KDE, and desktop environments in general, I'm primarily using applications developed for LXDE, XFCE, and Gnome. I have no problems with the former two, but I keep having conceptual difficulties with the ideologically driven minimalism of the latter. Take file managers and their associated terminal, for example. In PCManFM (LXDE), for example, one can change the associated terminal as expected in the program's preferences. Same in Thunar (XFCE). But of course not in Nautilus (Gnome) or any of its forks such as, for example, Nemo (Cinnamon). All of these “nonessential” settings have been dispelled to dconf, the ‘registry’ of Gnome, which can be accessed either with the dconf-editor or the command-line tool gsettings. For example, the following command changes the terminal associated with nemo to sakura:

gsettings set org.cinnamon.desktop.default-applications.terminal exec 'sakura'

I hope to remember that the next time instead of spending an eternity in the preferences again.

Modern times

Cobra — Sat, 05 Sep 2020 11:52:22 GMT

Since the beginning of time (or so it seems), I've had Emacs installed with the extension AUCTeX to handle LaTeX documents. And, mind you, I'm still using it from time to time! As a matter of fact, in 2018 I've worked on a number of manuscripts exclusively with Emacs to prepare myself for the editor shootout I've promised for the end of 2018 (and which may or may not be done by the end of this year). I'm still quite happy with it, that much I can say already now.

Perhaps you can then understand my surprise when yay told me that AUCTeX has been orphaned on the AUR. I was even more surprised when I saw that the maintainer was Stefan Husmann, who is also the maintainer of several hundred other packages and a moderator on the German Archlinux forum. Not the guy to thoughtlessly abandon a package on a mere whim.

And then it hit me: of course! Emacs has got it's own package manager (ELPA) some time, well, perhaps two years ... actually, eight years ago. 😣

So what's the meaning of this post? Let's say that there're one billion computer users out there. Only one percent of these know what an editor is, and only one percent of these again are actually using one. Of these again, only one percent use Emacs. Once again one percent of these Emacs users use AUCTeX, but more than 80% of these guys have installed AUCTeX via ELPA, the recommended and canonical way. I'm not one of them. Am I the only one? No, if we do the math, it turns out that there's one kindred spirit who is in the same situation like me. This post is for you, my brother in arms!

Well, as stated above, Emacs recommends installing AUCTeX via ELPA. After removing AUCTeX from the AUR, we can install manually

M-x package-install RET
auctex

or, in a properly maintained init.el (like mine), automatically:

(require 'package)

(add-to-list 'package-archives
        '("melpa" . "`https://melpa.org/packages/" <https://melpa.org/packages/">`_))

(package-initialize)
(when (not package-archive-contents)
        (package-refresh-contents))

(defvar myPackages
   '(better-defaults
         material-theme
         ein
         elpy
         flycheck
         py-autopep8
         ac-math
         auctex
         auto-complete-auctex
         ))

(mapc #'(lambda (package)
        (unless (package-installed-p package)
          (package-install package)))
          myPackages)

and

;;(load "auctex.el" nil t t)
;;(load "preview-latex.el" nil t t)

While I was pondering the question whether this post would be relevant for anybody at all, I found these news: Levee, a vi clone, has got a new major release after 30 years. Now that's the spirit! Compared to the estimated number of users interested in this update (interestingly, the only comment in the AUR is from Stefan Husmann), my post is for the masses. To celebrate this Chucknorishness of software development, I've installed levee and prepared this text in it. It was ok (just like vi), but David Parsons will certainly understand if I say that I prefer vim for everyday work.

SOHO system monitoring

Cobra — Sun, 16 Aug 2020 11:51:48 GMT

I have to admit that when computers are concerned, I'm somewhat of a control freak: for more than 20 years, a system monitor is an integral part of my desktop. Since the last 10 years, conky fills this role. Conky can be configured exactly to one's liking and actually may be a quite stylish element of the desktop. My conkies rather display a maximum of information while still being aesthetically pleasing (for me). Judge for yourself:

You can get the configuration file here, if you are interested.

Now, having an active element on the desktop can be distracting, and I understand that this may not be to everyone's liking (although I myself feel entirely detached from the system I'm working on without this direct view into the engine room). Besides, configuring conkies is also not something you could call simple and intuitive.

If you are a private or SOHO user, and are interested in an on-demand system monitor, it doesn't really help looking at the list of system monitors available on Wikipedia. For example, in the office we are quite happy with Nagios for monitoring the health of a few dozen servers, but it would be a bizarre overkill to employ it for the few systems in a SOHO situation.

If it's about monitoring a single system, the most obvious choice is bashtop, or, after a port to Python that happened just two weeks ago, bpytop, a system monitor for the command line that I'd mentioned already in a previous post. An interesting alternative that is graphically more spartan but no less capable is glances. Neither of these programs require configuration; they all work out of the box. Here are two screenshots showing bpytop running in mosh sessions on pdes-net.org and blackvelvet, my desktop. The former is virtualized and thus lacks CPU temperatures.

If bashtop/bpytop isn't sufficient, but configuring Nagios too much, I'd recommend a look at Monitorix, which requires very little configuration, and can be be accessed with a browser. I've deployed it on my office PC for being able to examine the computing resources on this system in very great detail from my living room. And that works really well: with the help of the Monitorix protocols, I can present solid evidence when asking for more RAM or storage place. 😎 Here's the very top of the monitorix report on my desktop, showing that I'm doing just fine with what I currently have. 😞

Working on the command line

Cobra — Mon, 01 Jun 2020 15:00:13 GMT

I was looking for an introduction like “Due to the Corona crisis, ...”, as everybody does these days. Unfortunately, that won't work with the subject I'm going to talk about, namely, command line (CLI) applications, which I've used and liked in the pre-SARS-CoV-2 world just as much as now. I'm convinced since ages that the CLI is, to state it with the words of Luke, “the most intuitive, most natural and easiest to grasp type of user interface we have invented so far”.

But regardless of what I and others believe or not, lots of things are simply best done on the command line. There's a catch, of course: that statement is only true if and only if we are equipped with the right tools. An ancient /bin/sh without tab completion and history search and no access to my toolbox is nothing but a nightmare. Correctly configured, however, nothing beats the CLI in terms of speed and economy.

In the following, I'll provide a brief overview of the command line applications I'm regularly using for everyday duties such as server administration and file management, as well as a few more enjoyable activities. Two of my earlier posts have a certain overlap with the present one, but a different focus. My list is of course by no means exhaustive: you can find many more interesting tools and gadgets, ranging from the useful to the bizarre (try ternimal). Excellent starting points are the curated lists provided by Adam and Marcel. In addition, Igor (the guy behind wttr) compiled a list of web services available via the command line.

Shell

Work on the command line starts with the shell. The default in most distributions is the bash, and in a few the zsh. Both require extensive configuration to offer all features I'd like to see, and not all distributions provide such a custom setup (meaning, you got to do it). In contrast, fish is very well configured out-of-the-box regardless of the distribution. For the typical bash one-liner copied from the interwebs, I usually follow this advice.

Terminal

If we are not at the console, we need a terminal emulator. I'm primarily using Tilix or, when resources are scarce, Guake and Terminator, but there are plenty of other choices.

Remote Shell

A lot of my everyday duties involve connecting to a remote server. Wherever possible, I do that by using a combination of mosh and tmux, the benefits of which have been described, for example, by Filippo and Brian. For example, I'd use

mosh pdes-net.org --tmux new-session -s default

for connecting to and starting a new tmux session with the name 'default' on this server. I can detach with Ctrl+A-D and attach anytime again (also from an entirely different network) with

mosh pdes-net.org --tmux a

Note that mosh requires some open UDP ports that may require configuration of the firewall (for which I'm utilizing ufw, so it's as easy as 'ufw allow <port>/udp').

Navigation and file management

Everybody with a certain sense of order tends to get pretty long path names, which are a nuisance to type regardless of tab completion. That's basically why file managers were invented! But there's a faster way: autojump. Instead of typing the path, you could just jump to it:

cobra at deepgreen in ~
↪ j pra20_3
/home/cobra/ownCloud/MyStuff/projects/publications/uwe/pra20_1-3/pra20_3
cobra at deepgreen in ~/o/M/p/p/u/p/pra20_3
↪ j portfolio
/home/cobra/Documents/aur/portfolio
cobra at deepgreen in ~/D/a/portfolio
↪ j pdes
/home/cobra/ownCloud/MyStuff/Documents/pdes-net.org
cobra at deepgreen in ~/o/M/D/pdes-net.org
(blog) ↪

There are several tools similar to autojump, some more powerful, but in contrast to these, it's also officially available for Debian. And I'm used to it. ☺

On systems with an SSD, I like to use broot, which is neither yet another autojumper, nor a full-blown file manager, but something in between. It's also nice as a tool to get information on file dates and sizes.

As an actual file manager, I much prefer nnn, although I always also install ranger as well as the good old mc. Don't underestimate the latter – it may look oldfashioned and outdated, but none of its more fashionable cousins allows, for example, remote sftp connections (although I usually simply use scp for copying files between remote locations). And there's another small but decisive difference between mc and nnn/ranger that may simplify file selection and renaming for most people (see the appendix to this post below).

Commands one googles sooner or later:

show/hide hidden files

nnn       .
ranger    zh
mc        Alt+.

disk usage

broot     :s
nnn       td or ta

Editor and other utilities

There can only be one: vim. Well: neovim. But that's it. 😉 In both cases, I use vim-plug as a plugin manager to load nnn as file opener (there is also a ranger plugin) and optionally vimtex whenever it's appropriate (although vim is not my primary TeX editor – a subject to which I will return in a forthcoming post). And if you really, really can handle neither vim nor emacs: try micro, it's the better nano. 😉

I put all documents that are still being edited under local version control. For this very simple task, I prefer mercurial over git because of the former's humanly readable version numbers (I just find it more natural and less demanding to address a commit with a natural number than with a hash). For LaTeX documents, I use scm-latexdiff to create diffs out of previous version managed by mercurial. And finally, I backup all of my documents and data with borg and rsync (and in future, also with rclone) as described in detail in my previous post.

Whatever I'm working on, it surely involves quick check on numbers, some simple, some involved. A lot of these can be done by qalc, a very versatile general purpose calculator, which has replaced calc after I've discovered that qalculate! also has a CLI...

System and network administration

Very much up on my list for this tasks are two rather unexpected tools, namely, a mail client and a scheduler. In fact, I rely on mutt (“All mail clients suck. This one just sucks less.”) for reading the mails sent by cronie. Whether I'm interested in the status of my hourly backups on the desktop or in the results of daily security checks on a remote server, this combination of tools is truly indispensable for getting important system messages. In the same category are tools for receiving security news and advisories such as newsboat with the appropriate feeds (or arch-audit on Arch), and of course the security auditing tool lynis.

On servers, I often want to know who's logged in on a system and what this user is running. For this task, htop is the swiss army knife, offering an excellent overview of all system resources and activities and also the possibility to manage them. In particular, htop helps to find (and end) amok running applications consuming too many precious CPU cycles and RAM. Even more information offers bashtop, a veritable system monitor for the command line. Applications running wild while accessing the mass storage can be easily identified by iotop, and disk resources can be checked on a partition level by pydf and on a file level by ncdu (or by broot and nnn as mentioned above). For a more in-depth analysis of systems, tools such as dstat may become helpful, but my general experience has been rather that it either works, or is broken.

When I have problems with the snappiness of the interwebs (which has become very rare), I first turn to mtr which often helps to find the culprit (although there isn't anything one can do if one of the hops is overloaded and suffers from package loss). Several helpful tools exist if the problem seems to be rather on my side, such as dnstop, iftop, nethogs, iptraf, and more, but I think that these tools merit a separate post.

Spare time

All work and no play makes Cob a dull snake. I stream videos using mpv and youtube-dl, like everybody else. I used to listen music by moc, but I've switched to cmus a few year ago. Similarly, I've exchanged irssi for weechat to talk to friends. When I feel like getting some news from the world outside, I fire up newsboat for a list of feeds that I find amusing. And for a quick reality check, nothing works better than mop displaying a ticker of my stocks. The very compact ticker.sh lured me into creating a permanent ticker on my desktop via conky integration, but I found that it distracts me way too much.

Appendix: bulk rename

For sake of example, let's create 101 files with touch rha{0..100}.barber, and let's rename them so that the numbers are all three digits (like, 004 instead of 4, 023 instead of 23). We can do that the easy or the hard way.

mc gives us the choice, namely, between shell patterns (globs) and standard regular expressions (regexes). The file selection dialog (press +) has an option 'Using shell patterns'. Let's select that and perform our self-imposed task in three simple steps: first, we select all files with a single digit number (+ rha?.*), then rename them with F6 / rha?.* / rha0?.*, and then all with a two digit number with F6 / rha ??.* / rha0??.* Now, that was easy, wasn't it?

ranger doesn't understand globs, but allows the use of regexes with the :filter (zf) and :mark commands. The renaming is sourced out to the system wide editor, i.e., vim in my case, where we can use the substitute command (:s) and vim regexes (which are mostly identical to those used in, for example, sed and perl, but not identical). So let's start with selecting all files with a single digit number: :mark -rft rha[0-9].b, followed by :bulkrename. The selected files can be easily renamed in vim by :%s/\([0-9]\)/0\1/g, followed by ZZ to save the list and apply it. For the next bunch, we mark files again by :mark -rft rha[0-9]..b, :bulkrename, and repeat the above command in vim. Not quite as easy as with mc if one is not very familiar with regexes!

nnn is very similar to ranger in this regard. We can select files by the filter function employing either strings (/) or regexes (\). So we type \rha[0-9].b followed by r to open the selected files in vim. The rest is basically the same as for ranger.

What you don't want to use, revisited

Cobra — Sat, 01 Jun 2019 16:58:12 GMT

A decade ago, I advised my readers to stay away from OpenOffice for the preparation of professional presentations, primarily because of the poor support of vector graphics formats at that time. In view of the difficulties we have recently encountered when working with collaborators on the same document with different Office versions, I was now setting great hopes in LibreOffice for the preparation of our next project proposal. First of all, I thought that using platform-independent open source software, it should be straightforward to guarantee that all collaborators are using the same version of the software. Second, the support for SVG has been much improved in recent versions (>6) of LibreOffice, and I believed that we finally should be able to import vector graphics directly from Inkscape into an Office document. Third, the TexMaths extension allows one to use LaTeX for typesetting equations and to insert them as SVG, promising a much improved math rendering at a fraction of the time needed to enter it compared to the native equation editor. Fourth, Mendeley offers a citation plugin for LibreOffice, which I hoped would make the management of the bibliography and inserting citations as simple as with BibTeX in a LaTeX document.

Well, all of these hopes were in vain. What we (I) had chosen for preparing the proposal (the latest LibreOffice, TexMaths extension, and Mendeley plugin) proved to be one of the buggiest software combos of all times.

ad (i): Not the fault of the software, but still kind of sobering: our external collaborator declared that he had never heard about LibreOffice, and that he wouldn't know how to install it. Well, we thought, now only two people have to stay compatible to each other. We installed the same version of LibreOffice (first Still, than Fresh), I on Linux, he on Windows. But the different operating systems probably had little to do with what followed.

ad (ii): I was responsible for all display items in the proposal, and I've used a combination of Mathematica, Python, Gimp, and Inkscape to create the seven figures contained in it. The final SVG, however, was always generated by Inkscape. I've experienced two serious problems with these figures. First, certain line art elements such as arrows were simply not shown in LibreOffice or in PDFs created by it. Second, the figures tended to “disappear”: when trying to move one of them, another would suddenly be invisible. The caption numbering showed that they were still part of the document, and simply inserting them again messed up the numbering. We've managed to find one of these hidden figures in the nowhere between two pages (like being trapped between dimensions 😱), but others stayed mysteriously hidden. We had to go back to the previous version to resolve these issues, and in the end I converted all figures to bitmaps. D'Oh!

ad (iii): I wrote a large part of my text in one session and inserted all symbols and equations using TeXMaths. Worked perfectly, and after saving the document, I went home, quite satisfied with my achievements this day. When I tried to continue the next day, LibreOffice told me the document is corrupted, and was subsequently unable to open it. I finally managed to open it with TextMaker, which didn't complain, but also didn't show any of the equations I had inserted the day before. Well, I saved the document anyway to at least restore the text. Opening the file saved by TextMaker with Writer worked, and even all symbols and equations showed up as SVG graphics, but without the possibility to edit them by TeXMaths.

ad (iv): Since my colleague had previously used the Mendeley plugin for Word, it was him who had the task to insert our various references (initially about 40). That seemed to work very well, although he found the plugin irritatingly slow (40 references take something like a minute to process). However, when he tried to enter additional references a few days later, Mendeley claimed that the previous one were edited manually, displayed a dialogue asking whether we would like to keep this manual edit or disregard it. Regardless the choice, the previous citations were now generated twice. And with any further citation, twice more, so that after adding three more citations, [1] became [1][1][1][1][1][1][1][1]. The plugin also took proportionally longer for processing the file, so in the last example, it took about 10 min. Well, we went one version back. But what worked so nicely the day before was now inexplicably broken. It turned out that a simple sync of Mendeley (which is carried out automatically when you start this software) can be sufficient for triggering this behavior. We finally inserted the last references manually, overriding and actually irreversibly damaging the links between the citations and the bibliography.

In the final stages, working on the proposal felt like skating on atomically thin ice (Icen 😎). We always expected the worst, and instead of concentrating on the content, we treated the document like a piece of prehistoric art which could be damaged by anything, including just viewing the document on the screen. That feeling was very distracting. I would have loved to correct my position, really, but LibreOffice in its present state is clearly no alternative to LaTeX for preparing the documents and presentations required in my professional environment. I will check again in another ten years. 😉

In principle, I would have no problem with being solely responsible for the document if I could use LaTeX and would get the contribution from the collaborators simply as plain text. It is them having a problem with that, since they don't know what plain text is. In this context, I increasingly understand the trend to collaborative software: it's not that people really work at the same time, simultaneously, on a document, but it's the fact that people work on it with the guaranteed same software which counts.

Modern file compression

Cobra — Sun, 10 Feb 2019 13:17:49 GMT

Unknown to most users, file compression silently works behind the scene. Updates for any operating system, for example, are compressed. That happens automatically and the user doesn't even need to know about it.

But sometimes, we have a choice. In Archlinux, for example, we can set the compression we'd like to use for packages created by makepkg (such as those installed over the AUR) – but how to chose between gz, bz2, xz, lrz, lzo, and z? And some backup software adds further options: Borg, for example, offers zlib, lzma, lz4, and zstd.

Most surprisingly, some of these algorithms have been developed only very recently: zstd comes from Facebook (2016), and there's brotli from Google (2015) and lzfse from Apple (2015). Why do these multi-billion-dollar companies develop compression algorithms? Because of the multi-billion dollars.

Instead of testing each of these algorithms yourself, you can use lzbench. It tests all open source algorithms of the lz family with the de facto standard file package in the compression business, the silesia suite.

Here are three examples geared toward high compression ratio, high speed compression, and high speed decompression:

High compression ratio (<25%)

➜  lzbench -c -ebrotli,11/xz,6,9/zstd,22 silesia.tar
lzbench 1.7.3 (64-bit Linux)   Assembled by P.Skibinski
Compressor name         Compress. Decompress. Compr. size  Ratio
memcpy                   9814 MB/s  9852 MB/s   211947520 100.00
brotli 2017-12-12 -11    0.48 MB/s   385 MB/s    51136654  24.13
xz 5.2.3 -6              2.30 MB/s    74 MB/s    48745306  23.00
zstd 1.3.3 -22           2.30 MB/s   600 MB/s    52845025  24.93

These are single core values. xz compression (but not decompression) profits from multithreading, while brotli and zstd do not.

High speed compression (for compression ratios <50%)

➜  lzbench -c -elz4/lzo1x silesia.tar
Compressor name         Compress. Decompress. Compr. size  Ratio
memcpy                   9861 MB/s  9768 MB/s   211947520 100.00
lz4 1.8.0                 524 MB/s  2403 MB/s   100880800  47.60
lzo1x 2.09 -12            521 MB/s   738 MB/s   103238859  48.71

High speed decompression (> 2000 MB/s)

↪ lzbench -c -elz4/lizard,10/lzsse8,6 silesia.tar
Compressor name         Compress. Decompress. Compr. size  Ratio
memcpy                   9579 MB/s 10185 MB/s   211947520 100.00
lz4 1.8.0                 525 MB/s  2421 MB/s   100880800  47.60
lizard 1.0 -10            421 MB/s  2115 MB/s   103402971  48.79
lzsse8 2016-05-14 -6     8.25 MB/s  3359 MB/s    75469717  35.61

What do we learn from these benchmarks?

If we want high compression reasonably fast, nothing beats xz. It's just perfect for what it's actually used by some (all?) Linux distributions: to distribute updates with acceptable computational resources over a channel with a very limited band width.
If the distributor commands over virtually unlimited resources, and compression speed is thus not an issue, brotli and zstd are clearly superior to all other choices. That's how we would like to have our updates: small and fast to decompress.
If size is not of primary importance, but compression speed is, lz4 and lzo are the champions.
If decompression speed is essential, lzsse8 wins. This is a lesser known member of the lz family and not widely available, in contrast to lz4 which thus scores again.

Weather widget

Cobra — Sun, 27 Jan 2019 14:56:42 GMT

To my great dismay, Yahoo announced earlier this year that their weather API will retire at January 3rd. And indeed, my little weather conky ceased to work at this day and thus reached its EOL. 😞

That's really too bad. Common forecast sites are peppered with dozens of javascripts and take ages to open on my Mini or my Lifebook. Here's an example which I find disagreeably slow even on my desktop. Besides, I also liked my weather conky for its aesthetic merit – at least _I_ found it pleasing to look at.

Well well well. There’s no point in crying over spilled milk. What are the options? There's conkywx, of course, the script collection for true weather aficionados. I look at it every second year and always feel that it's a tad overwhelming, at least for me, both with regard to features and visuals (one, two, three).

Alternatively, I could rebuild my weather conky around a new API – perhaps even the new Yahoo API. But I don't like to register anywhere for a simple weather forecast (and certainly not at Yahoo), and also don't want to spent more than, say, 15 min in getting a new forecast.

And then I found wttr.in – the fastest weather forecast ever. It's accessible by browser or in the terminal as a curl-based service, can be configured on the fly, and its ASCII graphs breath nerdy charm.

It's a one-liner in conky:

${execpi 3600 curl -s "wttr.in/Berlin?nT&lang=de" | head -n -2}

for a narrow (?n) and black-and-white (?T) view and

${execpi 3600 curl -s "wttr.in/Berlin?n&lang=de" | ~/.config/conky/ansito | head -n -2}

in full color thanks to ansito, which translates the ANSI color codes to the corresponding ones on conky.

But do we actually need a desktop widget when the forecast is so readily accessible? One could simple have an extra tab open in a browser, for example. Or, one could have a tab reserved for wttr.in in a Guake style terminal. For convenience, one could define an alias (works for all major shells) that updates the weather forecast every hour:

alias wttr='watch -ct -n 3600 "curl -s wttr.in/Berlin?lang=de | head -n -2"'

Hey, I like that. 😊