Adding minor getting started clarifications (#2798)

Author: jceipek

src/content/guides/environment-variables.md

@@ -7,13 +7,16 @@ contributors:
   - tbroadley
   - legalcodes
   - byzyk
+  - jceipek
 related:
   - title: The Fine Art of the webpack 3 Config
     url: https://blog.flennik.com/the-fine-art-of-the-webpack-2-config-dc4d19d7f172#d60a
 ---
 
 To disambiguate in your `webpack.config.js` between [development](/guides/development) and [production builds](/guides/production) you may use environment variables.
 
+T> webpack's environment variables are different from the [environment variables](https://en.wikipedia.org/wiki/Environment_variable) of operating system shells like `bash` and `CMD.exe`
+
 The webpack command line [environment option](/api/cli/#environment-options) `--env` allows you to pass in as many environment variables as you like. Environment variables will be made accessible in your `webpack.config.js`. For example, `--env.production` or `--env.NODE_ENV=local` (`NODE_ENV` is conventionally used to define the environment type, see [here](https://dzone.com/articles/what-you-should-know-about-node-env).)
 
 ```bash

src/content/guides/installation.md

@@ -30,7 +30,7 @@ npm install --save-dev webpack
 npm install --save-dev webpack@<version>
 ```
 
-If you're using webpack v4 or later, you'll need to install the [CLI](/api/cli/).
+If you're using webpack v4 or later, you'll also need to install the [CLI](/api/cli/).
 
 ``` bash
 npm install --save-dev webpack-cli