Sudokut is a command line solver for Sudoku puzzles. When supplied with a Sudoku string or file, it returns all possible solutions. It takes approximately half a second to solve a medium force Sudoku by using an efficient algorithm that is guaranteed to find all the solutions. It accepts many options that implement various features (validity check, diff, suggestions, and probing).
The Aida project is two-fold: it defines a simple common markup language designed to describe structured text, and it implements a compiler that translates the Aida syntax into various target formats (HTML, LaTeX, Trac, Mediawiki, Text, Markdown, and others). The system is fast, flexible, and extensible. The core command, aida, is a strict parser (written using Bison and Flex), which analyzes files written in the Aida Markup Language and invokes callbacks in order to convert them to the target format. It embeds a Tcl language interpreter and the callbacks are written in Tcl. This makes it very easy to extend the library and to define new target formats. Furthermore, the Aida files are highly parameterizable via a header and the entire system is configurable at the admin and at the user level. It is also possible to evaluate Tcl code within an Aida file and thus create dynamic contents.