## bc (command line calculator)

Why use a restricted graphical calculator when you have an arbitrary precision calculator *language* on the command line? Fire it up by typing *bc*. This will give you a new command
prompt where you can enter arithmetic expressions much like you're used to, e.g. 1+2 or 3*7. If you need the result of the last expression calculated, use the keyword *last*, for example:

*1+2*

*3*

*last+7*

*10*

You entered 1+2 and bc gave you the result 3. Then you added 7 to this intermediate result by typing *last*+7.

*bc* displays only one or two decimal places by default when doing floating point arithmetic. You can change this like so:

*scale=4*

This will make *bc* print up to 4 decimal places. Since *bc* is an arbitrary precision calculator language, the scale can be as large as 2147483647! You can save your favorite scale
value by adding the following line to your ~/.bashrc configuration file:

*export BC_ENV_ARGS=“$HOME/.bc_settings”*

In the file ~/.bc_settings (you can use any other file name), save your desired scale value, for example:

*scale=8*

Every time *bc* starts, it evaluates the file given by BC_ENV_ARGS.