Problem with external monitor via HDMI or matrix on screen?

 Try rollback to previous kernel 5.11

and execute command 

sudo ubuntu-drivers autoinstall

should be ok

Purge/uninstall Minecraft from Ubuntu

 

Example for Minecraft:

• Find out the package name:

  $ apt-cache search minecraft
  
  

• Purge the package and its dependencies:

  $ sudo apt-get autoremove --purge minecraft
  [...some output...]
  

perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset),

 

apt-get install multipath-tools

manually

export LANGUAGE=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8 

locale-gen en_US.UTF-8
dpkg-reconfigure locales 

or

edit /etc/profile

add this lines to this file

export LANGUAGE=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8 

can't set the locale; make sure $LC_* and $LANG are correct

 /etc/locale.gen

uncoment  

  en_GB.UTF-8
  en_US.UTF-8


run locale-gen as root

 

 

Virtualbox: two network interfaces

 I had to add the following lines in Debian virtual machine's /etc/network/interfaces file:

allow-hotplug eth1
iface eth1 inet dhcp

The second line instructs the interface to obtain an IP via DHCP. The first line loads the interface at boot time.

To apply the changes to a running system, invoke:

ifup eth1

The name for the eth1 interface may vary, use ifconfig -a to list all available interfaces.

EDIT: full /etc/network/interfaces:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

allow-hotplug eth1
iface eth1 inet dhcp

How to install ZOOM on Ubuntu 20.04.2 LTS

•  sudo apt-get upgrade
• sudo snap install zoom-client

Uninstall flatpak

1. sudo apt install flatpak 

2. flatpak uninstall --all 

3. sudo apt purge --autoremove flatpak

4. Check directory /var/lib/flatpak should be everything removed.