SpeedCrunch supports the accuracy of the calculations up to 50 decimal places. To manage the program can be fully from the keyboard without using the mouse, for all actions there are hotkeys. To enter a query string keys or by using the buttons on the calculator. When you enter the program will offer suggestions for features, if they are contained in the library, as well as syntax highlighting your request.
The program is available for Linux, Windows and MacOS X.
sudo apt-get install speedcrunch