Add content to Creating things section

lessons/shell/creating-things.md

@@ -2,6 +2,127 @@
 
 # Creating things
 
+The filesystem is comprised of directories and files.
+Here, we'll see how to make them.
+
+To start, change to the **Desktop** directory:
+```
+$ cd ~/Desktop
+/home/mpiper/Desktop
+```
+Note that by using the tilde `~`,
+we'll get to the Desktop from whereever we are in the filesystem.
+
+Next,
+use the `mkdir` command to make a new directory:
+```
+$ mkdir new
+$ ls
+data-shell  data-shell.zip  new
+```
+Change to the new directory and get a listing:
+```
+$ cd new
+$ ls
+```
+The new directory is empty.
+
+The `touch` command can be used to make a new, empty, file.
+```
+$ touch haiku
+$ ls -l
+total 0
+-rw-r--r--. 1 mpiper csdms 0 Jul 29 14:23 haiku
+```
+The `l` option to `ls` forces long output,
+which shows, among other things, that the file **haiku** has zero bytes.
+
+Let's add some content to this file.
+We'll do so with a *text editor*,
+an application that allows us to write in the file.
+Note that a text editor is different than a *word processor*
+(like Microsoft Word)
+which automatically applies markup and formatting to the text.
+
+There are many differnent text editors available;
+e.g., `vi`, `emacs`, `atom`, `sublime`,
+but the one we'll use here is called `nano`.
+It trades functionality for simplicity.
+
+Open the file **haiku** with `nano`:
+```
+$ nano haiku
+```
+The `nano` editor has a simple interface.
+Just type text.
+I'll enter the following:
+
+> Yesterday it worked  
+> Today it is not working  
+> Software is like that.
+
+(Funny, but computers are deterministic.
+If something's not working,
+it's likely because I did something wrong.)
+
+Once you've entered the text,
+hit the `Ctrl-x` key combination to save the file and exit.
+
+
+## Copying, moving, removing
+
+Let's make a copy of our haiku:
+```
+$ cp haiku haiku-1
+$ ls
+haiku  haiku-1
+```
+The `cp` makes a duplicate of a file.
+
+The `mv` command moves a file from one location to another.
+Let's move **haiku-1** up to the **Desktop** directory:
+```
+$ mv haiku-1 ~/Desktop
+$ ls
+haiku
+$ ls ~/Desktop/
+data-shell  data-shell.zip  haiku-1  new
+```
+Note that **haiku-1** has been moved from the **new** directory to **Desktop**.
+
+The `mv` command can also be used to rename a file.
+```
+$ mv ../haiku-1 haiku.copy
+$ ls
+haiku  haiku.copy
+```
+Here, we moved the file back to the **new** directory and renamed it.
+
+Files can be deleted with the `rm` command.
+Remove our haiku copy with
+```
+$ rm haiku.copy
+$ ls
+haiku
+```
+There is no concept of a "trash" or "recycle" bin in the shell.
+Once a file is removed, it's gone, irrevocably.
+
+As a last step,
+let's move our haiku up to the parent directory,
+change to the parent directory,
+then delete the **new** directory:
+```
+$ mv haiku ..
+$ cd ..
+$ rmdir new
+$ ls
+data-shell  data-shell.zip  haiku
+```
+As `rm` removes files,
+the `rmdir` command removes directories.
+However, the directory must be empty before it can be removed.
+
 
 ## Summary
 
@@ -13,15 +134,18 @@ described in this section.
 | mkdir            | creates a directory
 | touch            | creates an empty file
 | nano             | text editor
+| cp               | copies a file
+| mv               | moves or renames a file
 | rm               | deletes a file (permanently)
 | rmdir            | deletes a directory (permanently)
-| mv               | moves or renames a file
-| cp               | copies a file
 | Ctrl-a           | place cursor at start of line
 | Ctrl-e           | place cursor at end of line
 | Ctrl-k           | clear text to end of line
 | Ctrl-l           | clear text in terminal
 
+ 
+___
+
 [Introduction to the shell](./index.md) |
 Previous: [Files and directories](./files-and-directories.md) |
 Next: [Pipes and filters](./pipes-and-filters.md)