bash function for comparing version numbers

version_comparator.sh

#!/usr/bin/env bash

function version_gt() { test "$(printf '%s\n' "$@" | sort -V | head -n 1)" > "$1"; }
function version_eq() { test "$(printf '%s\n' "$@" | sort -V | head -n 1)" = "$1"; }
function version_lt() { test "$(printf '%s\n' "$@" | sort -V | head -n 1)" < "$1"; }

RUBY_VERSION=$(/usr/bin/ruby -v | awk '{print $2}' | cut -d'p' -f1)

echo "ruby version is ${RUBY_VERSION}"

if version_lt $RUBY_VERSION 2.4.0; then
    echo "ruby version is less than 2.4.0"
fi

if version_eq $RUBY_VERSION 2.0.0; then
    echo "ruby version is 2.0.0"
fi

if version_eq $RUBY_VERSION 2.3.3; then
    echo "ruby version is equal to 2.3.3"
fi

if version_gt $RUBY_VERSION 2.0.0; then
    echo "ruby version is greater than 2.0.0"
fi