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bootsplash-manager (Manjaro Xfce Linux)

In newer releases Manjaro Xfce is booting with an animated splash screen (animation with three white dots on a black screen, "plymouth splash"), not displaying the textual boot log any more. When booting gets stuck, this may lead o missing informations. To prevent this, and return to more classical booting style, the "bootsplash-manager" can be used. there, switch to "boot log" profile.

It probably maintains /etc/default/grub file, entry GRUB_CMDLINE_LINUX_DEFAULT where the tag "quit" gets removed, and "splash" remains unchanged. "nomodeset" seems not to be added.


$ journalctl --since today
can help to see the most recent boot log.

$ inxi --admin --verbosity=7 --filter --no-host --width
can help to see an overview of all hardware components.

Keyring (gnome-keyring) automatisch bei Login öffnen (Manjaro Xfce Linux)

Bei Wahl der Option User-Autologin ist ein automatisches Öffnen eines Keyrings nicht sicher möglich. Deshalb muss - falls User-Autologin genutzt wird - das User-Autologin abgestellt werden ("autologin-user" Eintrag in "/etc/lightdm/lightdm.conf" auskommentieren).
Danach mit "seahorse" einen Keyring anlegen, welcher den Namen "login" trägt (lowercase ist nötig). Das Passwort für den Keyring soll identisch sein mit dem User-Passord. Der Keyring "login" wird dann bei explizitem User-Login automatisch während des Login-Vorgangs geöffnet.
Stop system consuming/capturing/occupying Keyboard Bindings - blocking IntelliJ IDEA
(Manjaro Xfce Linux)

There are at least two places to have a look at, regarding settings, which typically consume a lot of keyboard bindings by default.
  • "xfce4-keyboard-settings" (Keyboard settings)
    Goto to tab "Application shortcuts"
    Remove Ctrl-Alt-F, Ctrl-Alt-P, and many others
  • "xfwm4-settings" (Window Manager)
    To check its bindings, go to tab "Keyboard"
    Here are e.g. Ctrl+Alt+Arrow Keys and Shift+Ctrl+Alt+Arrow Keys predefined (to move window to workspace edges). If you like to reuse those keys in your application (e.g. IDE), then remove those in xfwm4-settings first.
    Also, Ctrl-F1 .. Ctrl-F9 may be removed as they get in the way of IntelliJ IDEA.
CPU Informationen ermitteln (Linux)

$ hwinfo --cpu
CPU Monitoring in System Tray (Manjaro Xfce Linux)

Software package:
xfce4-cpugraph-plugin

It is important to add the icon directly in the Panel Items list, do not try to add it via a panel item called "launcher".
(It only works to add by adding a panel item directly without a launcher.)

Optional list elements, on item separated lists, Cats-Parse (Scala)

Please email me.
QEMU/KVM Clipboard Sharing

Host/Guest Operation System Needed Software Component
Host Manjaro Xfce Linux spice-vdagent
Guest Windows 10 spice-guest-tools
Console ANSI Colors Output

Depending on your Console or IDE application, ANSI colors might be displayed differently. Here is a small Scala test frame helping identify ANSI color codes by example printout ("rainbowing"). Repository on GitHub
MediaTek MT7921k Wi-Fi 6E 80MHz nutzen
(Manjaro Xfce Linux)

  • 1. "inxi -N" liefert die Adapter Kennung. Es ist erforderlich, den Linux Kernel auf 5.16.14. upzudaten.
  • 2. Das MT7921k Modell von Mediatek hat die Besonderheit, dass teilweise ein 60 Sekunden Power Shutdown (PC ganz aus, stromlos, für 60 Sekunden) nötig ist, um die Karte aktivierbar zu machen.
Diese obigen Punkte können Abhilfe schaffen, wenn WLAN Verbindungen trotz vorhandener Hardware im System nicht angezeigt werden.
draw.io: too many annoying "unsaved changes" popups

draw.io desktop e.g. version 22.0.3 - but probably other versions too - have problems with file save and reload later, sometimes a dialog appears mentioning "unsaved changes", and the user has to decide how to proceed. The message appears too often in my eyes. A work-around is: Goto menu "Extras" (in some themes its called "Settings" instead), then "Drafts ...", then enter "0" (zero) in the field "Draft save interval [sec] (0 to disable):".
That fixes the problem as far as I can observe.
CPU Stress

command line:
$ stress --cpu 16
um z.B. die CPU mit 16 Cores zu belasten. Nutzlich fur Stresstests.
Listen der Services (ArchLinux)

systemctl --user --type=service
Beispiel:
$ systemctl --user --type=service
  UNIT                                LOAD   ACTIVE SUB     DESCRIPTION                                                 
  at-spi-dbus-bus.service             loaded active running Accessibility services bus
  dbus.service                        loaded active running D-Bus User Message Bus
  dconf.service                       loaded active running User preferences database
  gnome-keyring-daemon.service        loaded active running GNOME Keyring daemon
  gvfs-afc-volume-monitor.service     loaded active running Virtual filesystem service - Apple File Conduit monitor
  gvfs-daemon.service                 loaded active running Virtual filesystem service
  gvfs-gphoto2-volume-monitor.service loaded active running Virtual filesystem service - digital camera monitor
  gvfs-metadata.service               loaded active running Virtual filesystem metadata service
  gvfs-mtp-volume-monitor.service     loaded active running Virtual filesystem service - Media Transfer Protocol monitor
  gvfs-udisks2-volume-monitor.service loaded active running Virtual filesystem service - disk device monitor
  obex.service                        loaded active running Bluetooth OBEX service
  pipewire.service                    loaded active running PipeWire Multimedia Service
  pulseaudio.service                  loaded active running Sound Service
  xdg-desktop-portal-gtk.service      loaded active running Portal service (GTK/GNOME implementation)
  xdg-desktop-portal.service          loaded active running Portal service
  xdg-document-portal.service         loaded active running flatpak document portal service
  xdg-permission-store.service        loaded active running sandboxed app permission store
  xfce4-notifyd.service               loaded active running XFCE notifications service

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.
18 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
Finagle ohne absehbaren Support für Scala 3

Leider ist die Scala Middleware und Web Service Lösung Finagle aktuell nicht für Scala 3 vorbereitet. Der Entwicklungsstand scheint eingefroren zu sein. Die Aussichten auf eine baldige Änderung sind - offen gesagt - eher trüb. Die Firma Twitter scheint anstelle dessen künftig auf Akka zu setzen.
Ein Finagle Crosscompile auf Scala 3 ist jedoch möglich.
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gvfs smb samba Links on Desktop

GVFS stands for GNOME Virtual File System.
Under Manjaro, if You want create a desktop link refering to a gvfs/samba/smb location, this can be tricky when done with copy & paste with the mouse and modifier keys (alt, shift, ctrl) (copy, move, create link). Personally, for me the easiest and most robust way to accomplish the goal is to use "thunar" file manager, and its right-click-on-file function "Send To", "Desktop (Create Link)". This way a valid reference is created, in the form e.g.:
/run/user/1000/gvfs/smb-share:server=myservername,share=myhostname/myfilepath

If problems arise, try adding ",user=myuserid" before "/myfilepath"
with "ln -s targetpath name" a link can be recreated.
To analyze if the links are feasible, try "ls -al" in the directory where the links are stored. if the links are not feasble, the color of the "ls" entry will indicate this (e.g. red font, flashing).
See also: id_mv9umquc6tux, id_47b19ukgsdp1
git: non-bare zu bare repository

Development Maschinen als Client nutzen können, in Verindung zu einem mit ssh verbundenen git Server, dessen working tree ausgecheckt ist und auf dem Server ebenso editiert wird (non-bare).
Nicht immer ist die neue git "push-to-deploy" Funktion praktikabel, insbesondere nicht, wenn am Server der ausgecheckte working tree nicht read-only ist, sondern auch dort aktiv editiert wird. In diesem Fall kann "push-to-deploy" zu Problemen führen, nämlich dann, wenn Server-seitig Änderungen noch nicht commited wurden, aber ein Client bereits push-t. "push-to-deploy" ist eher geeignet für z.B. git non-bare readlony Webcontent auf Webservern.
Wenn man zusätzliche Development Maschinen als Client mit dem git Server verbinden mag, ist es vermutlich besser, serverseitig ein bestehendes non-bare repostiory in ein bare repository zu übertragen, und daraus dann ein "zweites" non-bare repository abzuleiten (wiederum auf dem Server), mit ausgechecktem working tree.
"git clone --bare quelle1 ziel.git"
danach kann man "ziel.git" - Server zu Server - clonen:
"git clone ziel.git quelle2"
"quelle1" ist dann obsolet (als Backup ggf.), "quelle2" ist dann verwendbar.
In "quelle2" zeigt z.B. "git ls-remote" die Verbindung zum neuen bare repository. Dieses server-seitige bare repository kann man dann z.B. über ssh von den Development Maschinen aus erreichen. Anlegen z.B. - vom Server zum Client - auf dem Client, mit "git clone myuserid@myservername:/serverpath/ziel.git". Anmerkung: Die bare Eigenschaft eines git repositories erkennt man üblicherweise bereits am Foldername, der auf .git endet. Darin gibt es dann keinen working tree und keinen .git subfolder wie bei den non-bare repositories üblich.
obs, Logitech C920 webcam, Lagging (Manjaro XFCE Linux)

To solve the lagging issue, in obs go to Video Capture source -> Properties -> Video Format (third Option in the list) -> de-select YUYV 4:2:2 -> select Motion-JPEG instead (e.g.)
Error mounting filesystem, wrong fs type ntfs (Linux)

One possible solution:
Mount explicitly by command.
E.g.
$ sudo mount -t ntfs /dev/sda2 /mnt/xyz01
or
$ sudo mount -t ntfs3 /dev/sda2 /mnt/xyz01
redshift ad-hoc / explicit temperature (Linux)

Set temperature:
$ redshift -O 1000

Reset:
$ redshift -x

Script in Autostart einhängen, für automatische, explizite Festlegung nach Login:

#!/bin/bash
sleep 3
redshift -x
redshift -O 1400

Anmerkung: Das Programm "redshift" in Autostart nicht aktivieren.

autologin (Manjaro Xfce)

1. Prüfen, ob User bereits in autologin Gruppe:
$ getent group autologin autologin:x:1000:myusername

2. Prüfen der Datei "/etc/pam.d/lightdm-autologin".
Nötig ist ein Eintrag der Form:
auth [success=1 default=ignore] pam_succeed_if.so user ingroup autologin

3. "/etc/lightdm/lightdm.conf" benötigt einen Eintrag der Art "autologin-user=myusername"

Collation version mismatch

The error message
PostgreSQL collation version mismatch
The database was created using collation version 2.36, but the operating system provides version 2.37.
might be caused by updating the host operating system's glibc, which is responsible for collation implementations, and which the database is using in turn. When collation versions between host and database differ, this may lead to the message above. Typically it doesn't occur in stable versions of host operation systems, but in test versions.
Logitech G203, Linux

To adjust settings at "Logitech G203 LightSync" (with 3 LEDs) device, "piper" can be used. But the Manjaro package "piper" and its prerequisite "ratbag" / "ratbagd" are not yet identifing this specific hardware model.

To work-around this issue, remove "piper" and "ratbag" packages, and install "piper-git" and "ratbag-git" packages via AUR. Then a "$ killall ratbagd" to stop the old service should suffice, then restart "piper" (it starts the new "ratbagd" implicitly), and then you can adjust the LEDs and other things.

Please note: Currently is only one LED color for all three LEDs simultaneously possible, not three different colors.

Minimized Windows auslassen, beim Alt-Tab Navigieren durch die Liste der Anwendungen (Manjaro XFCE)

"Window Manager Tweaks" (xfwm4-tweaks-settings) -> Tab. "Cycling" -> uncheck: "Include hidden (i.e. iconified) windows
Watching Scala 3 macro compile time println's / log entries in IntelliJ

Q: When I try out a Scala 3 macro, the inline definition of the macro itself with the splicing, and the function which e.g. is using quotations, when I compile this in sbt I get printed all macro println's to the console at compile-time, as it is expected.
However, when I switch to IntelliJ with the Scala plugin, bsp and bloop compile server installed, those macro println's are missing when I compile, and even I looked into any log I could open, but could not find those macro println's. Any idea how I could see those printlns in Intellij? I am using BSP, Bloop, Scala Compile Server. I slightly suspect that compile server output does not reach Intellij build console.
A: Instead of using the hidden IntelliJ BSP Bloop compile server, in an IntelliJ console tool window, run "sbt ~compile" (while being pwd'ed in the correct project path).
IntelliJ will use this as the build server (since it won't start two at the same time - sytem-wide) and you will see the macro compile-time println log entries in this sbt console printout.
Alt + Mouse Wheel Zoom (Manjaro Xfce Linux)

Alt + Mouse Wheel Zoom (Manjaro Xfce) can be accomplished by calling "xfce4-settings-editor", selecting channel "xfwm4", then enabling property "zoom_desktop".
Slow launch of firefox, files, and other applications - since Manjaro XFCE Update 2023-05 (regression issue)

e.g. 1 minute waiting time before launch instead of 2 seconds, as it has been before the Manjaro update.
Interim solution:
add "xdg-desktop-portal-gnome" software package, afterwards, remove it.
Reboot.
Hardware Info zur CPU: lstopo

Hardware Info zur CPU, mit Graphik (CPUs, Cores)

Software package: lstopo

Whisker Menu - Super Left (Windows) key
(Manjaro Xfce Linux)

  • in the keyboard settings "xfce4-keyboard-settings", assign xfce4-popup-whiskermenu --pointer
    to Super Left key (windows key)
  • if then unintentionally a desktop context menu gets opened ("create launcher, create url link, create folder, create document, ..." etc.) then the reason could be that there is one superfluous setting active.
    Goto " session and startup", open "Application Autostart" tab, then deactivate the xcape entry: xcape -e 'Super_L=Alt_L|F1'
vscode bug (Manjaro Xfce Linux), Open External Terminal not working: Ctrl + Shift + c

1. first check the vscode setting "terminal.external.linuxExec"
2. the official release directly from Microsoft has fixed this issue already. so deinstalling the distribution package, and instead using the Microsoft download, should work (if you want pay the "price").
3. as a work-around until this bug is fixed in the distribution package, instead of external terminal, the internal terminal panel works. execute command ( Ctrl + Shift + p ) "Toggle Terminal ": ( Ctrl + Shift + ´ ) then a internal terminal panel opens. if more terminals are needed, then: right click in the terminal area, "New terminal".
Prolog Integration

Teilweise sind Bereiche der Anwendung stark regelbasiert und lassen sich nur mehr recht als schlecht mit prozeduralen Programmiersprachen realisieren. Hier können Subsysteme zum Einsatz kommen, welche in Prolog implementiert sind.

Typische fachliche Bereiche für Logik Engines sind z.B. Berechtigungen, Optimierungen, Compliance.

Logik-Berechnungen sind generell "costly", lassen sich aber auch cachen, damit die Performance nicht darunter leidet. swi Prolog ist eine der vielen möglichen Implementierungen einer Prolog Engine.

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