PyShell (Originally called "Bitt") Is a little shell written in plain Python and is completely Open-source for you to fork or edit. It has a config.json file to give you some control if not familiar with writing python (or any language at all), just edit the text in the configuration file.
You can input math problems (i.e 1 + 1 or 5 ** 2) or comparason over numbers (i.e 1 < 1) or some commands like print or var (print well prints the inputted text and var assigns a value to a variable name of your choice) More commands will come out soon.
print, var, and math.