| [M4](http://www.gnu.org/software/m4/m4.html) | GNU M4 is an implementation of the traditional Unix macro processor. It is mostly SVR4 compatible although it has some extensions (for example, handling more than 9 positional parameters to macros). GNU M4 also has built-in functions for including files, running shell commands, doing arithmetic, etc. |
| [ncurses](http://www.gnu.org/software/ncurses/) | The Ncurses (new curses) library is a free software emulation of curses in System V Release 4.0, and more. It uses Terminfo format, supports pads and color and multiple highlights and forms characters and function-key mapping, and has all the other SYSV-curses enhancements over BSD Curses. |
