Adding and multiplying numbers using a shell script

Question

I am learning shell scripts, I am trying to write a small script that adds and multi-digit number as shown below. But the value is not displayed

value=212
amt=`expr "( $value * 2 + ( $value * 2 * .075 ) ) " | bc`
echo $amt

+3

Ban 13 jul. 15 at 18:12

2 answers

Jahid · Answer 1 · 2015-07-14T07:18:53+0000

Your given code works fine, but I intend to suggest some improvements:

Example:

value=212
amt=$(echo "( $value * 2 + ( $value * 2 * .075 ) ) " | bc)
echo $amt

Output:

455.800

Steven penny · Answer 2 · 2015-07-14T00:49:18+0000

First of all. It:

value * 2 + (value * 2 * .075)

is a hot mess, this is equivalent to:

value * 43 / 20

Next, I prefer to use awk for this task:

#!/usr/bin/awk -f
BEGIN {
  value = 212
  print value * 43 / 20
}