How do I get bc(1) to print the leading zero?

Question

I do something like the following in a Makefile:

echo "0.1 + 0.1" | bc 

(in the real file the numbers are dynamic, of course)

It prints .2 but I want it to print 0.2.

I would like to do this without resorting to sed but I can't seem to find how to get bc to print the zero. Or is bc just not able to do this?

Answer 1

You can also resort to awk to format:

 echo "0.1 + 0.1" | bc | awk '{printf "%f", $0}' 

or with awk itself doing the math:

 echo "0.1 0.1" | awk '{printf "%f", $1 + $2}' 

Answer 2

This might work for you:

echo "x=0.1 + 0.1; if(x<1) print 0; x" | bc