BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
Cactus is a general, modular, parallel environment for solving systems of partial differential equations. The code has been developed over many years by a large international collaboration of numerical relativity and computational science research groups and can be used to provide a portable platform for solving any system of partial differential equations.
Drqueue is a distributed rendering queue. It helps manage jobs on a render farm. It works under Linux, Mac OS X, FreeBSD, IRIX, and Windows, supports Maya, Blender, Lightwave, Mental Ray, Bmrt (Renderman), 3Delight, and Pixie out of the box, and can support any other renderer or computing task that can be handled via scripting.
JSBSim is a multi-platform flight dynamics model. The FDM is essentially the physics/math model that defines the movement of an aircraft under the forces and moments applied to it using the various control mechanisms and from the forces of nature. JSBSim has no native graphics. It can be run by itself as a standalone program, taking input from a script file and various aircraft configuration files, or it can be run as an integrated part of a larger flight simulator implementation that includes a visual system. The most notable usage example is the FlightGear simulator. JSBSim models the aerodynamic forces and moments by the classic coefficient buildup method.
The MirBSD Korn Shell (mksh) is an actively developed successor of pdksh (the Public Domain Korn Shell), aimed at producing a shell good for interactive use, but with the primary focus on scripting. It is intended to be portable to most *nix-like operating systems as long as they're not too obscure. mksh incorporates improvements from OpenBSD and Debian, as well as bugfixes and enhancements developed for the MirOS, FreeWRT, and MidnightBSD projects and Android. The emacs command line editing mode is UTF-8 capable, and Byte Order Marks are ignored in scripts. The shell supports large files, as well as all pdksh and some csh, AT&T ksh, zsh, and GNU bash features, is compatible with the Bourne shell and POSIX (within limits), has no limit on array sizes, and incorporates some other useful builtins and features. While being already fast and small (without losing functionality), flags to make it even smaller can be given at compile time. An interactive shell reads "~/.mkshrc" on startup.
Mrxvt (previously known as materm) is a multi-tab X terminal emulator based on rxvt/aterm. It supports multiple tabs, runtime dynamic tab title, pseudo-transparent backgrounds, user-supplied background images (JPEG, PNG, or XPM), background color tinting, text shadows, NeXT/rxvt/xterm/SGI style scrollbars, XIM, multiple languages (Chinese, Korean, and Japanese) and logging. It is lightweight and fast, and only depends on Xlib.
MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). Merging of 2 or more log files is possible. It can also use colors while displaying the log files (through regular expressions) for faster recognition of what is important. It can also filter lines (again with regular expressions). It has interactive menus for editing given regular expressions and deleting and adding windows. One can also have windows with the output of shell scripts and other software. When viewing the output of external software, MultiTail can mimic the functionality of tools like 'watch'.
SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.
cgrep provides many of the features of grep, egrep, and fgrep with enhanced performance along with many additional features. One of the most important features is the ability to output the context (surrounding lines) of the matching lines. The context window may be specified as a constant number of lines before and after the matching lines, by specifying beginning and ending delimiters, or various combinations thereof.