A simple, fast, and intuitive command-line calculator written in Go.

Install calc as you would any other Go program:

go get github.com/alfredxing/calc

You can use calc in two ways: shell mode and command.

This is probably the mode you'll want to use. It's like the python shell or irb. The shell mode uses the terminal package provided by golang.org/x/crypto/ssh/terminal, which means it supports many of the shell features you know and love (like history, pasting, and the exit command).

> 1+1
2
> 3(5/(3-4))
-15
> 3pi^2
29.608813203268074
> @+1
30.608813203268074
> @@@*2
-30
> ln(-1)
NaN

You can also use calc to evaluate an expression with just a single command (i.e. without opening the shell). To do this, just use calc [expression]:

bash$ calc 1+1
2
bash$

calc supports all the standard stuff, and I'm definitely adding more later (also feel free to fork and add your own!)

+, -, *, /, ^, %

sin, cos, tan, cot, sec, csc, asin, acos, atan, acot, asec, acsc, sqrt, log, lg, ln, abs

e, pi, π

Previous results can be accessed with the @ symbol. A single @ returns the result of the last computation, while multiple @ gets the n^th last result, where n is the number of @s used (for example, @@ returns the second-last result, @@@@@ returns the fifth-last result).

• Google
  • Doesn't work without an internet connection
  • Slower
  • Doesn't show previous computations, so you end up with multiple tabs open at once.
• Spotlight (on OS X)
  • No history
  • Switching between Spotlight and other windows isn't too fun
• Python/IRB
  • Requires use of a separate math module for most functions and constants
  • A little bit slower to start up
• bc
  • Limited number of built-in functions; these have shortened (not too intuitive) names as well.

The alternatives above are all great, and have their own advantages over calc. I highly recommend looking into these if you don't like how calc works.