In this article, I shall list down the useful software packages I have installed in my Ubuntu (18.04.2 LTS 64-bit) operating system.  I used the following commands to install them just after a fresh install of the OS.

Some General and Basic Packages:

sudo apt-get update
sudo apt-get install gnome-shell gftp gparted djview4 diffuse vim-gnome linuxdcpp vlc

The first command updates the package list of the system.  The command sudo apt-get install followed by the name of the packages (separated by space) installs those packages from Ubuntu repositories.

Some image editing softwares:

sudo apt-get install gimp inkscape

Version Control System:

sudo apt-get install git

Python:

sudo apt-get install python3 python3-pip python3-numpy python3-scipy python3-matplotlib python3-dev ipython3 ipython3-notebook mercurial python3-sphinx spyder3

Fortran:

sudo apt-get install gfortran libopenmpi-dev openmpi-bin liblapack-dev libfftw3-dev libfftw3-doc

gfortran installs the GNUFortran compiler.  The next two packages install OpenMPI libraries and executables respectively.  The last one installs the standard linear algebra package LAPACK.  Note that gfortran comes with OpenMP libraries pre-installed.

Plotting:

sudo apt-get install gnuplot

(This post will be updated as and when I find other useful packages.)