How to compare two floating point numbers in Bash?

Question

I am trying hard to compare two floating point numbers within a bash script. I have to variables, e.g.

let num1=3.17648e-22
let num2=1.5

No

Answer 1

I was posting this as an answer to https://stackoverflow.com/a/56415379/1745001 when it got closed as a dup of this question so here it is as it applies here too:

For simplicity and clarity just use awk for the calculations as it's a standard UNIX tool and so just as likely to be present as bc and much easier to work with syntactically.

For this question:

$ cat tst.sh
#!/bin/bash

num1=3.17648e-22
num2=1.5

awk -v num1="$num1" -v num2="$num2" '
BEGIN {
    print "num1", (num1 < num2 ? "<" : ">="), "num2"
}
'

$ ./tst.sh
num1 < num2

and for that other question that was closed as a dup of this one:

$ cat tst.sh
#!/bin/bash

read -p "Operator: " operator
read -p "First number: " ch1
read -p "Second number: " ch2

awk -v ch1="$ch1" -v ch2="$ch2" -v op="$operator" '
BEGIN {
    if ( ( op == "/" ) && ( ch2 == 0 ) ) {
        print "Nope..."
    }
    else {
        print ch1 '"$operator"' ch2
    }
}
'

$ ./tst.sh
Operator: /
First number: 4.5
Second number: 2
2.25

$ ./tst.sh
Operator: /
First number: 4.5
Second number: 0
Nope...