Merge pull request #96 from ESMValGroup/nano-everywhere-77

Use nano everywhere

Author: SarahAlidoost

_episodes/03-configuration.md

@@ -36,7 +36,7 @@ path to your home directory. Note that files and directories starting with a
 period are "hidden", to see the `.esmvaltool` directory in the terminal use
 `ls -la ~`.
 
-We run a text editor called Nano to have a look inside the configuration file:
+We run a text editor called ``nano`` to have a look inside the configuration file:
 
 ~~~bash
   nano ~/.esmvaltool/config-user.yml

_episodes/04-recipe.md

@@ -157,12 +157,23 @@ wget https://raw.githubusercontent.com/ESMValGroup/ESMValTool_Tutorial/master/da
 {: .solution}
 
 > ## Explore the recipe
-> Use the following command and investigate the sample recipe.
+> We use the text editor ``nano`` to investigate the sample recipe.
 > ~~~bash
-> vim  recipe_example.yml
+> nano recipe_example.yml
 > ~~~
 {: .challenge}
 
+> ## Text editor side note
+>
+> No matter what editor you use, you will need to know where it searches
+> for and saves files. If you start it from the shell, it will (probably)
+> use your current working directory as its default location. We use ``nano``
+> in examples here because it is one of the least complex text editors.
+> Press <kbd>ctrl</kbd> + <kbd>O</kbd> to save the file,
+> and then <kbd>ctrl</kbd> + <kbd>X</kbd> to exit ``nano``.
+> The line numbers can be shown by pressing <kbd>alt</kbd> + <kbd>shift</kbd> + <kbd>3</kbd>.
+{: .callout}
+
 Please note the following sections:
 
   - documentation: lines 4-20