how to add floating number in shell?-CodePudding

a=-1.4
b=42273.85
awk "BEGIN {print ($a   $b)}"

42272.4

I am expecting result as 42272.45, what is wrong here?

CodePudding user response：

You didn't specify a precision so awk picked one for you (%.6g, the default for CONVFMT, see https://www.gnu.org/software/gawk/manual/gawk.html#Built_002din-Variables):

a=-1.4
b=42273.85
awk -v a="$a" -v b="$b" 'BEGIN {printf "%.2f\n", (a   b)}'
42272.45

I'm also correcting your use of shell variables in an awk script above, see How do I use shell variables in an awk script?.

CodePudding user response：

One solution to do floating point math in sh, bash, zsh and more is using bc

echo "$a   $b" | bc
42272.45

Using awk you can override the internal default output format by using printf

awk -v a="$a" -v b="$b" 'BEGIN{printf("%.2f\n", a   b)}' 
42272.45