- Install Virtualbox and Ubuntu 20.04
 -  Install Ubuntu 20.04 packages that are needed to install R
		 
## Run the system commands (in a command line terminal): sudo apt update sudo apt install build-essential -y sudo apt install gfortran -y sudo apt install libreadline-dev -y sudo apt install libx11-dev -y sudo apt install libxt-dev -y sudo apt install zlib1g-dev -y sudo apt install libbz2-dev -y sudo apt install liblzma-dev -y sudo apt install libpcre3-dev -y sudo apt install libcurl4 libcurl4-openssl-dev -y sudo apt install texlive-full -y sudo apt install libssl-dev -y sudo apt install libxml2-dev -y sudo apt install openjdk-11-jre-headless -y sudo apt install openjdk-11-jdk-headless -y # sudo apt install pcre2-utils -y sudo apt install libpcre2-dev -y sudo apt install libopenblas-dev -y sudo apt install liblapack-dev -y # sudo apt install vim -y -  Install openssh  (Ref: https://www.simplified.guide/ubuntu/install-ssh-server)
		 
## Run the system commands: sudo apt update sudo apt install openssh-server -y sudo systemctl status ssh ## SSH login without password (http://www.linuxproblem.org/art_9.html) ssh-keygen -t rsa cat .ssh/id_rsa.pub >> .ssh/authorized_keys -  Install Python-3.6
		 
## Run the system commands: sudo add-apt-repository ppa:deadsnakes/ppa sudo apt install python3.6 -y sudo apt install python3.6-dev -y pkg-config --list-all |grep python -  Install R-3.6.1
		 
## Run the system commands: wget https://cran.r-project.org/src/base/R-3/R-3.6.1.tar.gz tar -zxvf R-3.6.1.tar.gz cd R-3.6.1 # Using the default location, /usr/local ./configure --with-x=yes --enable-R-shlib CFLAGS=' -g3 -pthread -Wall -Wnested-externs -pedantic' CXXFLAGS=' -pthread -lpthread' # make clean make sudo make install # Checking: pkg-config --cflags libR pkg-config --libs libR ## Add the following line to the bash run-commands file ~/.bashrc ## to set the environment variable R_HOME export R_HOME=$(pkg-config --variable=rhome libR) # or export R_HOME="/usr/local/lib/R" ## ## Start a new command terminal application which R R CMD config --all |grep local -  Install the 
devtoolsR package (optional)# Start R R #In R do install.packages("devtools") # in case of errors ... install.packages("usethis") install.packages("devtools") -  Install the 
supr3package (Not in RStudio)- supr3_22.02.02.tar.gz Wed Feb 2 10:48:19 EST 2022
 - supr3.pdf Wed Feb 2 10:48:19 EST 2022
 
 - Network configuation
		
Follow the follwing steps to set network settings for your Ubuntu machines
-  Find the main menu of the VirtualBox App (Oracle VM Vitualbox Manager), 
Click File → Host Network Manager...
Create vboxnet0 (auto-created name), and enable DHCP server -  For each guest machine, Choose the guest machine (in VirtualBox App),
	
Click Settings → Network → Adapter 2 and
Enable Network Adapter → Select Attached to "Host-only Adapter"; Name: "vboxnet0" -  Start Ubuntu guest machines and check network settings, for example, with
	the Ubuntu command
	
ip -c a 
 -  Find the main menu of the VirtualBox App (Oracle VM Vitualbox Manager), 
 - Install Guest Addition
	
To install Guest Addition in any VirtualBox OS follow these steps:
- Click on Devices menu → Choose Insert Guest Additions CD imageā¦
 - Follow the instructions
 
 - Shared Folders
	
- Create a folder on the host machine to be shared. For example on Mac, Settings → Share → Enable File Sharing
 -  Create a shared folder on the guest machine:
	
- Select Devices → Shared Folders...
 - Choose the Add button
 - Select a folder
 -  Tick the Auto-mount checkbox.
		
	To have access to these shared mounted folders, users in the guest need to be a member of the group vboxsf.
This can be done by running the command:
sudo usermod -aG vboxsf userName
The guest machine will need to restart to have the new group added. - Select the Make permanent option
 
 -  Create a subdirectory in a shared folder to be used as
		
SUPR_HOME_USERinstead of the default subdirectory ~/.supr. Alternatively, create a symbolic link to this subdirectory by running the command
# mv ~/.supr ~/.supr_save
ln -s SomeSharedFolder/SuprUserDir ~/.supr
 
 - Clone Virtual Machines to Create a Virtaul Cluster
	
Right-click on the guest machine, select the Clone... option, and follow the instructions.
- Change the computer name on Ubuntu Linux
		(Ref: https://www.cyberciti.biz/faq/ubuntu-change-hostname-command/):
	
-  Type the following command to edit /etc/hostname using nano or vi text editor:
sudo nano /etc/hostname
Delete the old name and setup new name. -  Next Edit the /etc/hosts file:
sudo nano /etc/hosts
Replace any occurrence of the existing computer name with your new one. -  Reboot the system to changes take effect:
sudo reboot 
 -  Type the following command to edit /etc/hostname using nano or vi text editor:
 - Add host entries to the 
/etc/hostsfile, one line for each host in the format in the example:127.0.0.1 localhost 127.0.1.1 Ubuntu-03 192.168.56.101 Ubuntu-01 192.168.56.102 Ubuntu-02 192.168.56.103 Ubuntu-03 # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 
 - Change the computer name on Ubuntu Linux
		(Ref: https://www.cyberciti.biz/faq/ubuntu-change-hostname-command/):
	
 - Miscellaneous Topics
        
- Commands for mounting file systems: mount and umount
 - VBoxManage application on the host machine
 
 
Example: Ubuntu 20.04 LTS with Base Memory: 2048 MB, Storage: 40 GB