calculate a+b or a*b instantly on the command line or in a batch file with sfk calc for Windows, Mac OS X and Linux.

sfk calc "1+2"

do a simple calculation of two values.

options
   -dig[its]=n  round result to n digits.

web reference
   http://stahlworks.com/sfk-calc

examples
   sfk calc "1.5*2.5"
     prints 3.75. quotes "" are required
     with linux but not under windows.