Question

I am using this command

num1=2.2
num2=4.5

result=$(awk 'BEGIN{print ($num2>$num1)?1:0}')

This always returns 0. Whether num2>numl or num1>num2
But when I put the actual numbers as such

result=$(awk 'BEGIN{print (4.5>2.2)?1:0}')

I would get a return value of 1. Which is correct.

What can I do to make this work?

Answer 1

The reason it fails when you use variables is because the awk script enclosed by single quotes is evaluated by awk and not bash: so if you’d like to pass variables you are using from bash to awk, you’ll have to specify it with the -v option as follows:

num1=2.2
num2=4.5

result=$(awk -v n1=$num1 -v n2=$num2 'BEGIN{print (n2>n1)?1:0}')

Note that program variables used inside the awk script must not be prefixed with $