As one of the earliest computer chess programs with full source code available, it is one of the oldest for Unix-based systems and has since been ported to many other platforms.

[4] For comparison, the strongest human player, Magnus Carlsen, has achieved an Elo rating of 2882.

On the same list, Fritz 8 was rated at 2665 Elo,[5] and that program in the 2004 Man vs Machine World Team Championship beat grandmasters Sergey Karjakin, Veselin Topalov and reached a draw with Ruslan Ponomariov.

It is often used in conjunction with a GUI program such as XBoard or GNOME Chess, where it is included as the default engine.

Since version 6.1 GNU chess supports a graphical mode for terminal emulators.