unix shell scripting subtraction for floating point numbers

问题

#!/bin/ksh

a=8.3
b=10.20
diff=`expr $b - $a`
echo "$diff"

its giving

expr: 0402-046 A specified operator requires numeric parameters. error i want output as 1.9

回答1:

You don't need bc for this, use the native arithmetic operators in ksh

#!/bin/ksh

a=8.3
b=10.20
printf "%.2f\n" "$((b - a))"

outputs

$ ksh script.ksh
1.90

来源：https://stackoverflow.com/questions/41059906/unix-shell-scripting-subtraction-for-floating-point-numbers