#!/usr/bin/env bash

set -o pipefail  # trace ERR through pipes
set -o errtrace  # trace ERR through 'time command' and other functions
set -o nounset   ## set -u : exit the script if you try to use an uninitialised variable
set -o errexit   ## set -e : exit the script if any statement returns a non-true return value

function versionCompare () {
    if [[ $1 == $2 ]]
    then
        echo -n '='
        return
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            echo -n '>'
            return
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            echo -n '<'
            return
        fi
    done

    echo -n '='
}

versionCompare "$1" "$2"
