Plotutils

GNU plotutils is a set of free software command-line tools and software libraries for generating 2D plot graphics based on data sets. It is used in projects such as PSPP and UMLgraph, and in many areas of academic research, and is included in many Linux distributions such as Debian. Windows and Mac OS X versions are also available. The library provides bindings for the C and C++ languages. Its stand-alone command-line tools can generate graphs and perform numerical calculation of spline curves and systems of ordinary differential equations. Plotutils is a GNU package and is distributed under a free software licence, the GPL.
History.
Several utilities were inspired by Unix plotting utilities. A graph utility and various plot filters were present in the first releases of Unix from Bell Laboratories. By the time of Version 7 Unix, `graph', `plot', `spline', and several device-dependent versions of `libplot' were a standard Unix features. The first display device supported by the package was a Tektronix 611 storage scope. By the early 1980s, numerous other devices were supported.
In 1989, the first GNU versions of `graph', `plot', `tek2plot', `spline' and their respective documentation were written. Richard Stallman further directed development of the programs and documentation. The distribution, as it stood in 1991, was distributed under the name `GNU graphics'.
In 1995 the package was significantly expanded by writing a device-independent, standalone version of `libplot', and by rewriting `graph' from scratch, turning it into a real-time filter.