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*3"

do a simple calculation with mathematical
operators + - * /

options
   -dig[its]=n  round result to n digits
   -form        also print the formula,
                tab separated after result
   -sum         add values from chain text

experimental brackets support
   you may add option -bra[ckets] to use formulas
   with brackets, like
      sfk calc -bra 1.0/(1.0-1.0/(3+5)*9)
   however this is an experimental feature.
   wrong calculations may occur with brackets,
   on highly complex formulas. therefore:
   - counter-check the output with an alternate
     calculator before using a command repeatedly.
   - if you really find formulas that calculate
     wrong, supply samples in the sfk forum.

chaining support
   can use chain input data as #text within formula.

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

examples
   sfk calc "1.0+2.5*3.5"
     prints 9.75. quotes "" are required
     with linux but not under windows.
   sfk echo "1+2*3" +calc "#text*4"
     calculates 1 + 2*3*4 = 25
   sfk echo "1+2*3" +calc "#text" +calc "#text*4"
     calculates (1+2*3) * 4 = 28
   sfk filt in.txt +calc "#text" -form
     calculate all formulas given in in.txt
   sfk list -size -tabform sfk.exe +filt -utabform "#col1"
    +calc "#text/1000" -dig=0
     show the size of sfk.exe in kbytes, rounded to
     zero digits after decimal point.  [29]
   sfk filt in.csv -utabform "#col2" +calc -sum -dig=2
     if in.csv contains two tab-separated columns like
        apple	1.00
        banana	1.50
        pineapple	2.50
     then add prices from the second column.