Show apt package description from the command line

$: apt show ssh

This will show package description for ssh.

Show listening ports in Ubuntu using netstat

$: sudo netstat -tulpn

Install EF Core 3.1 Preview 3 in Ubuntu

To install Entity Framework Core 3.1.x Preview 3, do:

$: dotnet tool install --global dotnet-ef --version 3.1.0-preview3.19554.8
$: export DOTNET_ROOT=$HOME/.dotnet

Note that I am using local install of .Net Core 3.1 Preview 3 hence the need to export DOTNET_ROOT.

Install .Net Core 3.1 preview 3 in Ubuntu

$: cd ~/
$: mkdir tmp
$: cd tmp
$: wget https://dotnetwebsite.azurewebsites.net/download/dotnet-core/scripts/v1/dotnet-install.sh
$: chmod +x dotnet-install.sh
$: ./dotnet-install.sh -Version 3.1.100-preview3-014645
$: export PATH="$HOME/.dotnet:$PATH"

Install Chromium browser in Ubuntu

Chromium is the free and open source web browser developed by Google. To install it in Ubuntu do:

$: sudo apt install chromium-browser

Free math applications

List of free math applications:

Maxima - computer algebra system (link)
GNU Octave is a high-level language, primarily intended for numerical computations (link)
Python + scipy + matplotlib + ipython + pylab - python based numerical package (link - various )
R - a language and environment for statistical computing and graphics (link)
Sage (link)
Scilab -  is an open source, cross-platform numerical computational package and a high-level, numerically oriented programming language(link)

HowTo: Get Ubuntu version from the command line

Method 1

$: cat /etc/os-release | grep PRETTY_NAME

Method 2

$: cat /etc/issue

Method 3

$: lsb_release -d -s