Fixed comflict with linux install instructions

Author: Thomas Preston

docs/installation.rst

@@ -97,7 +97,7 @@ Disable Serial Port Login Shell
 -------------------------------
 CodeBug uses the serial port which is configured to output the login
 shell by default. You must disable this before CodeBug will work. To do
-so, run:
+so, run::
 
     sudo raspi-config
 
@@ -107,11 +107,13 @@ then reboot.
 
 Install Python
 --------------
-Python should already be installed but for good measure::
+Python 3 and pip should already be installed but for good measure::
 
+    sudo apt-get update
+    sudo apt-get upgrade
     sudo apt-get install python3
 
-To install pip, securely download `get-pip.py <https://bootstrap.pypa.io/get-pip.py>`_.
+If pip isn't installed you can securely download it from here `get-pip.py <https://bootstrap.pypa.io/get-pip.py>`_.
 
 Then run the following::
 
@@ -122,7 +124,7 @@ Install codebug_tether
 ----------------------
 To install codebug_tether, open up a terminal and type::
 
-    pip3 install codebug_tether
+    sudo pip3 install codebug_tether
 
 To test it has worked, plug in CodeBug and open a Python shell by typing::