calc
A simple, fast, and intuitive command-line calculator written in Go.
Fork of https://github.com/alfredxing/calc to add additional functions/changes
Install
Install calc as you would any other Go program:
go get github.com/hjf288/calc
Usage
You can use calc in two ways: shell mode and command.
Shell mode
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
Command
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$
Supported functions, operators, and constants
calc supports all the standard stuff, and I'm definitely adding more later (also feel free to fork and add your own!)
Operators
+
, -
, *
, /
, ^
, %
Functions
sin
, cos
, tan
, cot
, sec
, csc
, asin
, acos
, atan
, acot
, asec
, acsc
, sqrt
, log
, lg
, ln
, abs
Constants
e
, pi
, π
History
Previous results can be accessed with the @
symbol. A single @
returns the result of the last computation, while multiple @
gets the nth last result, where n is the number of @
s used (for example, @@
returns the second-last result, @@@@@
returns the fifth-last result).
Why not use ...?
- 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.