How do I validate decimal numbers?

Question

Hi I'm working on an assignment and got stuck on this part, how do I validate decimal numbers/numbers in shell?

It can accept numbers but not decimal numbers. I want it to be able to accept both.

This is what I have so far

if echo $value | egrep '^[0-9]+$' >/dev/null 2>&1 ; then
echo "OK"
else
echo "There Is An Error"
echo "Please Try Again"
fi

Answer 1

Instead of using grep, you can use the bash to check expression:

#!/bin/bash

value=98.23
if [[ "$value" =~ ^[0-9]+(\.[0-9]+)?$ ]]
then
   echo good
else
   echo bad
fi