Update 01_setting_up.md

new_basic_shell/01_setting_up.md

@@ -4,9 +4,23 @@ author: "Sheldon McKay, Mary Piper, Radhika Khetani, Emma Berdan"
 ---
 
 ## Learning Objectives
+- Understand what the shell is
 - How do you access the shell?
 
 
+## What even is shell?
+
+You have likely heard the words bash, shell, unix, and linux before but may not know what they mean or how they relate. Before we even access the shell let's try to understand these terms.
+
+* Unix is simply an operating system much like Windows or macOS. Unix and its "flavors" are the operating systems you find on high perfomance computing clusters. 
+* Linux can be thought of as a clone or "flavor" of unix. The main difference between unix and linux is that unix is proprietary (i.e. requires a license) while linux is open source.
+
+  ![Foxtrot by Bill Amend](img/open_sores.png)
+  *Foxtrot by Bill Amend*
+
+* Shell is a general term for a command line interpreter which is a program that lets users control their operating system with text commands. Shell has been described as user-facing “shell around the computer’s whirring innards” ([Louis Pouzin](https://en.wikipedia.org/wiki/Louis_Pouzin))
+* Since shell is a general term there are many different shells. The most prevalent is bash which is short for "Bourne-Again SHell" which replaced the original Bourne shell that was NOT developed by [Jason Bourne](https://en.wikipedia.org/wiki/Jason_Bourne) but by [Stephen Bourne](https://en.wikipedia.org/wiki/Stephen_R._Bourne) a programmer at Bell labs. 
+
 ## Starting with the shell
 
 **With Macs**