This tutorial explains comparing two numbers for equal or not in bash and shell programming

How to Check whether two numbers are equal or not in Bash

This program takes input values and checks if two values are the same or not.

first=13
second=15
if (( first == second )); then
  echo "Two numbers are equal";
fi

Some shell scripts do not support (()), use [[]] with Comparison operators

Following are Comparison operator

-eq: equal -ne : Not equal -lt : Less than -le : Less than equal -gt : Greater than -ge: Greater than or equal

used the -eq operator in the if fi conditional statement

first=13
second=15

if [ "$first" -eq "$second" ]; then
  echo "Two numbers are equal";
fi

You can also do it with the ternary operator

first=13
second=15

echo $(( first == second ?  "equal": "not equal" ))