added sections

README.md

@@ -11,6 +11,7 @@ tilde.town.
 # Table of contents
 
 <!-- markdown-toc start - Don't edit this section. Run M-x markdown-toc-refresh-toc -->
+
 - [Requirements](#requirements)
 - [Conventions used in this handbook](#conventions-used-in-this-handbook)
 - [Getting started](#getting-started)
@@ -20,9 +21,11 @@ tilde.town.
     - [For cmdr users](#for-cmdr-users)
     - [For PuTTY users](#for-putty-users)
     - [Testing out your command line interface](#testing-out-your-command-line-interface)
+- [Understanding UNIX-related concepts](#understanding-unix-related-concepts)
     - [Understanding your home directory](#understanding-your-home-directory)
     - [Understanding directory and file permissions](#understanding-directory-and-file-permissions)
     - [Understanding commands](#understanding-commands)
+    - [Understanding package managers](#understanding-package-managers)
 - [Basic UNIX commands](#basic-unix-commands)
 
 <!-- markdown-toc end -->
@@ -132,10 +135,14 @@ on a computer sends data somewhere. In this case, the text
 representing your files and directories is the data, and that text is
 being sent to your screen.
 
-# Understanding your home directory
+# Understanding UNIX-related concepts
 
-# Understanding directory and file permissions
+## Understanding your home directory
 
-# Understanding commands
+## Understanding directory and file permissions
+
+## Understanding commands
+
+## Understanding package managers
 
 # Basic UNIX commands