roll is a command line tool which simulates rolling a die like those used in Dungeons and Dragons, the Pen and Paper role playing game.

$ pip install git+https://github.com/davidhaller/roll.git

Run the roll script from your command line. You will get a shell-like prompt where you can enter roll commands like this:

$ roll
roll> 1d20 + 4
[15] + 4 = 19
roll> 2d8
[6, 1] + 0 = 7
roll> 3 * d6 - 1
[6] - 1 = 5
[3] - 1 = 2
[4] - 1 = 3

Quit the program by typing exit or quit.

You can also pipe commands into roll:

$ echo "1d12 + 3; 1d4; 6d6 - 1" | roll
[8] + 3 = 11
[3] + 0 = 3
[5, 6, 4, 2, 1, 6] - 1 = 23

If you want bash-like command history controlled by your arrow keys, I recommend using rlwrap, which should be available through your distribution's package repository.

$ rlwrap roll

You will only need a Python interpreter installed. No external dependencies required.