Apache powerful and widely used free and open-source web server
argparse free and open-source Python module that facilitates use of command line arguments with Python scripts
Blender free and open-source 3D rendering program
Bokeh free and open-source library for visualizing data with interactive plots and graphics
Boost large, well-maintained set of C++ libraries
Bootstrap free and open-source front-end web framework
C++ low-level, compiled programming language
cmus lightweight, free and open-source, ncurses, command-line music player
Debian popular distribution of the free and open-source Linux operating system
Django free and open-source back-end web framework allowing quick deployment of common web functionality
GIMP free and open-source 2D raster graphics editor
GNU Compiler Collection widely-used free and open-source C/C++ compiler
GNU Emacs powerful and flexible free and open-source text editor
GNU Make free and open-source build automation tool for C/C++ software projects
GNU Scientific Library free and open-source C/C++ library for heavy-duty numerical computation
GNU Screen free and open-source, command-line terminal multiplexer
GuitarTuna nifty guitar tuner app for Android
ImageMagick free and open-source utility for converting image file types, primarily from the command-line
Inkscape free and open-source 2D graphics editor specializing in vector graphics
KaTeX lightweight JavaScript library for embedding LaTeX in web pages
LaTeX digital typesetting and document preparation system
Linode well-established virtual private server (VPS) provider
Linux family of free and open-source operating systems
Linux commands list of ~10 Linux commands that can be useful
Lynx lightweight, free and open-source, text-based web browser
Mathematica powerful computing package with excellent symbolic computation capabilities
matplotlib free and open-source Python module within the NumPy / SciPy stack for plotting data
MPI Message Passing Interface, a standard for communication among networked computers to facilitate parallel computation
Musicbrainz Picard free and open-source software for updating audio file metadata using the open Musicbrainz database
MySQL widely-used open-source relational database
NetworkX free and open-source Python module for analysis and visualization of graphs
NumPy free and open-source Python module for numerical computation
OpenSCAD free and open-source computer-aided design program
pdftk command-line pdf toolkit for joining, splitting, modifying pdf documents
PHP programming language that allows mixture of static HTML with dynamically generated HTML
phpMyAdmin free and open-source PHP web interface for managing MySQL databases
Python versatile, easy-to-learn, interpreted programming language
Raspberry Pi low-power, credit-card-sized computer
Raspbian distribution of the free and open-source Linux operating system tailored to run on a Raspberry Pi
rsync powerful Linux command-line utility for file transfer and synchronization across computers
SciPy free and open-source Python module for scientific computation; cousin of NumPy
Slurm free and open-source job scheduler for Linux/Unix-like computer clusters
subprocess free and open-source Python module for making system calls and interacting with the underlying OS
Ubuntu popular and well-supported distribution of the free and open-source Linux operating system
virtualization running an OS software layer on top of another software layer, rather than on hardware directly
VX ConnectBot Secure Shell (SSH) app for Android
WeeChat lightweight, free and open-source, ncurses, command-line chat client for IRC, etc.