How to Encrypt and Decrypt Files With GPG on Linux

https://www.howtogeek.com/427982/how-to-encrypt-and-decrypt-files-with-gpg-on-linux/

boot virtualbox from usb

https://www.aioboot.com/en/boot-from-usb-in-virtualbox/

2 Ways to Create an ISO from a Bootable USB in Linux

https://www.tecmint.com/create-an-iso-from-a-bootable-usb-in-linux/

How to change welcome message (motd) on Ubuntu 18.04 server

/etc/update-motd.d/

https://linuxconfig.org/how-to-change-welcome-message-motd-on-ubuntu-18-04-server

R-linux export QT_X11_NO_MITSHM=1

CODE: SELECT ALL

X Error: BadAccess (attempt to access private resource denied) 10
  Extension:    130 (MIT-SHM)
  Minor opcode: 1 (X_ShmAttach)
  Resource id:  0x13d
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 5 (X_ShmCreatePixmap)
  Resource id:  0x2a00013
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a00014
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a00014
X Error: BadPixmap (invalid Pixmap parameter) 4
  Major opcode: 54 (X_FreePixmap)
  Resource id:  0x2a00014
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 2 (X_ShmDetach)
  Resource id:  0x2a00013
X Error: BadAccess (attempt to access private resource denied) 10
  Extension:    130 (MIT-SHM)
  Minor opcode: 1 (X_ShmAttach)
  Resource id:  0x13d
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 5 (X_ShmCreatePixmap)
  Resource id:  0x2a0001e
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a0001f
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a0001f
X Error: BadPixmap (invalid Pixmap parameter) 4
  Major opcode: 54 (X_FreePixmap)
  Resource id:  0x2a0001f
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 2 (X_ShmDetach)
  Resource id:  0x2a0001e
[zerophase@localhost ~]$ sudo rlinux
X Error: BadAccess (attempt to access private resource denied) 10
  Extension:    130 (MIT-SHM)
  Minor opcode: 1 (X_ShmAttach)
  Resource id:  0x13d
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 5 (X_ShmCreatePixmap)
  Resource id:  0x2a0000f
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a00010
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a00010
X Error: BadPixmap (invalid Pixmap parameter) 4
  Major opcode: 54 (X_FreePixmap)
  Resource id:  0x2a00010
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 2 (X_ShmDetach)
  Resource id:  0x2a0000f
X Error: BadAccess (attempt to access private resource denied) 10
  Extension:    130 (MIT-SHM)
  Minor opcode: 1 (X_ShmAttach)
  Resource id:  0x13d
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 5 (X_ShmCreatePixmap)
  Resource id:  0x2a0001a
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a0001b
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2a0001b
X Error: BadPixmap (invalid Pixmap parameter) 4
  Major opcode: 54 (X_FreePixmap)
  Resource id:  0x2a0001b
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 2 (X_ShmDetach)
  Resource id:  0x2a0001a





Just add 

export QT_X11_NO_MITSHM=1



to gui working

Solving slowdown in NoMachine performances with GNOME 3

Just leave the gnome 3 heavy graphical manager and use somewhat lighter. for example gnome fall back or mate.


https://www.nomachine.com/AR12L00831
https://www.nomachine.com/AR07K00676
https://www.nomachine.com/AR07K00676

Optimal mapped mesh on the circle

Very nice description about how make mapped mesh on a two-dimensional circle can be found here

Add your user to the group - CentOS 7 & Virtual Box

 sudo usermod -G vboxsf -a myusername

How to Configure Internet access on a CentOS Minimal install

May

By default a CentOS minimal install can't connect to the network or the internet, in order to configure it to access the outside world you need to follow the following steps:

1. Configure the DHCP client on the default network interface eth0 by executing the following command:

dhclient eth0

2. Edit the main network configuration file to make sure networking is enabled using the command

vi /etc/sysconfig/network

and make sure that it has networking set to yes

NETWORKING=yes

3. Edit the network configuration file for eth0 to enable it to use a dynamic ip using dhcp

vi /etc/sysconfig/network-scripts/ifcfg-eth0

4. Modify the file to have the following

DEVICE="eth0"
BOOTPROTO="dhcp"
ONBOOT="yes"
NM_CONTROLLED="no"

4. Save the file and then restart the network service using the following command

service network restart

5. Make sure that eh0 has pulled an IP using the following command

ifconfig

Tun Ubuntu 18.04 in Enhanced Mode in Hyper-V

Hyper-V

Install ubuntu in generation 2 mode
Un-check secure boot

Ubuntu OS

#Get the scripts from GitHub
$ sudo apt-get update
$ sudo apt install git
$ git clone https://github.com/jterry75/xrdp-init.git ~/xrdp-init

#Make the scripts executable and run them...
$ cd ~/xrdp-init/ubuntu/18.04/

$ sudo chmod +x install.sh
$ sudo ./install.sh
$ reboot

Windows powershell in administratoe mode:

Set-VM -VMName Ubuntu -EnhancedSessionTransportType HvSocket

Log-in

UNCHECK Printers in local resources.

Unable to start the geometry editor ANSYS WB on CENTOS

export LD_LIBRARY_PATH=/usr/ansys_inc/v172/Framework/bin/Linux64/Mesa

sudo nano ~/.bashrc

export LD_LIBRARY_PATH=/usr/ansys_inc/v180/Framework/bin/Linux64/Mesa