diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/intro_aim.md b/2020/2020-02-15_gnuLinuxCourse/slides/intro_aim.md
index 992e314d5ce66bafe37c64c3f027a49031b24c6e..82ac41923f28367c988b52b1560b7e756821336d 100644
--- a/2020/2020-02-15_gnuLinuxCourse/slides/intro_aim.md
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/intro_aim.md
@@ -1,33 +1,16 @@
# Aims of the Tutorial
-
-* Connect to a GNU/Linux server
- + SSH, a de-facto standard for secure communication
-
- <!-- .element: class="fragment" -->
- + For Windows users
- - [MobaXterm][1] (_recommended by R3_)
- - [PuTTY][2], simple, ugly, but efficient and open source and does only SSH
+* Gain Familiarity With the Unix Shell
+ - And hint at ways it can be harnessed to give great power to the
+ user
- <!-- .element: class="fragment" -->
- + For Mac and GNU/Linux users, OpenSSH command line client
-
- <!-- .element: class="fragment" -->
-
<!-- .element: class="fragment" -->
-* Explore how to use the shell effectively
- * We will use bash which is (almost) universaly present
- - Steve Jobs did not like the license, but ...
- ```shell
- brew install bash
- ```
-
- <!-- .element: class="fragment" -->
+* Connect to a GNU/Linux server
+ + Using SSH, a de-facto standard for secure communication
+
+<!-- .element: class="fragment" -->
- <!-- .element: class="fragment" -->
-<!-- .element: class="fragment" -->
-[1]: https://mobaxterm.mobatek.net/download-home-edition.html
-[2]: https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
+<!-- <iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/A-HIlNGczgU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> -->
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/intro_first.md b/2020/2020-02-15_gnuLinuxCourse/slides/intro_first.md
index 51fc2d7c19db2d51788e9de2555b561dc242df91..0865c661f5f44d9008c2035c8c9d86bba61f43cc 100644
--- a/2020/2020-02-15_gnuLinuxCourse/slides/intro_first.md
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/intro_first.md
@@ -11,7 +11,8 @@
<!-- .element: class="fragment" -->
+ GNU/Linux user since [Debian Woody][5] (ca 2002)
- + Arrived as a seven CD set from a small computer shop from the [Getting Debian][6]
+ + Arrived as a seven CD set from a small computer shop from the
+ list of international vendors at [Getting Debian][6]
<!-- .element: class="fragment" -->
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/list.json b/2020/2020-02-15_gnuLinuxCourse/slides/list.json
index 294a1356765da975c2a80cd7c7c207463173ca53..4b966d753c72d5b5d4135b7c9af3e190181529b8 100644
--- a/2020/2020-02-15_gnuLinuxCourse/slides/list.json
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/list.json
@@ -3,6 +3,11 @@
{ "filename" : "intro_first.md"},
{ "filename" : "intro_beforewebegin.md"},
{ "filename" : "intro_aim.md"},
+ { "filename" : "shell.md"},
+ { "filename" : "shell/start.md"},
+ { "filename" : "shell/effective-cmd-editing.md"},
+ { "filename" : "shell/cp-mv.md"},
+ { "filename" : "shell/rm.md"},
{ "filename" : "ssh_intro.md"},
{ "filename" : "ssh_intro_2.md"},
{ "filename" : "ssh_intro_3.md"},
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/shell.md b/2020/2020-02-15_gnuLinuxCourse/slides/shell.md
new file mode 100644
index 0000000000000000000000000000000000000000..3ca1780838213739bc7ffba0501774cd58f5b7ad
--- /dev/null
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/shell.md
@@ -0,0 +1,62 @@
+# The Barrier between the Human and the Machine
+<div class="multicol">
+
+<div class="col" data-markdown>
+
+* What is a shell?
+ - Omnipresent user interface
+
+ <!-- .element: class="fragment" -->
+ - It interprets commands given by the user
+
+ <!-- .element: class="fragment" -->
+ - It is heavily keyboard based
+
+ <!-- .element: class="fragment" -->
+
+<!-- .element: class="fragment" -->
+
+* Shell runs within a terminal application
+ - In ancient times, these were actual pieces of hardware
+
+ <!-- .element: class="fragment" -->
+ - Today, a program that echoes user input and displays command results
+
+ <!-- .element: class="fragment" -->
+
+<!-- .element: class="fragment" -->
+
+* How to access it?
+ - **GNU/Linux systems:**
+ - Depends on the desktop interface (of which there are many)
+ - Access from a `Start`-like menu, or a `Win`-key search as
+ *terminal*, or *console*
+ - if all else fails, `Ctrl` + `Alt` + `F[2-6]`
+
+ <!-- .element: class="fragment" -->
+ - **Windows:** [MobaXterm][1] which you hopefully installed
+
+ <!-- .element: class="fragment" -->
+ - **Mac:** Built-in terminal; *Spotlight* search for *terminal*
+
+ <!-- .element: class="fragment" -->
+
+<!-- .element: class="fragment" -->
+
+</div>
+
+<div class="col" data-markdown>
+
+<img src="variae/figs/shell/3270.jpg" width="90%" />
+
+<!-- .element: class="fragment" -->
+
+</div>
+
+</div>
+
+
+[terminal]: variae/figs/shell/3270.jpg "IBM 3270"
+
+[1]: https://mobaxterm.mobatek.net/download-home-edition.html
+
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/shell/cp-mv.md b/2020/2020-02-15_gnuLinuxCourse/slides/shell/cp-mv.md
new file mode 100644
index 0000000000000000000000000000000000000000..3c4cc1275dc5af7a7c55259d49c7170525646eaa
--- /dev/null
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/shell/cp-mv.md
@@ -0,0 +1,16 @@
+# File Explorer: Copy(cp), Move(mv) and Remove(rm) File Operations
+
+```console
+$ mkdir linux-practical-03
+$ cp linux-practical-01/pr1-hello-world.txt linux-practical-03/pr3-hello-world.txt # cp arg1 arg2: copy file arg1 to file arg2
+$ mkdir linux-practical-03/dump
+$ cp -R linux-practical-01 linux-practical-03/dump # Copy the entire content of linux-practical-01
+$ # to dump subdirectory of linux-practical-03
+$ ls linux-practical-03/dump # Check if linux-practical-01 is there.
+$ # Move one up in history, jump to the beginning of the line ('Ctrl'+'A'), then
+$ # replace 'ls' with 'mv'
+$ # From then on ...
+$ mv linux-practical-03/dump linux-practical-03/dump2 # Congratulations, you just renamed dump to dump2.
+$ ls linux-practical-03 # Check the content. The directory dump should not exist.
+
+```
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/shell/effective-cmd-editing.md b/2020/2020-02-15_gnuLinuxCourse/slides/shell/effective-cmd-editing.md
new file mode 100644
index 0000000000000000000000000000000000000000..2590bdd914ff33bd99d48e198b24dc3682324303
--- /dev/null
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/shell/effective-cmd-editing.md
@@ -0,0 +1,32 @@
+# Practical: Effective Command Line Editing
+
+```console
+$ # Move up the history list until 'mkdir linux-practical-01'.
+$ # Move cursor using word motions 'Ctrl' + 'Left', or
+$ # 'Ctrl' + 'Right' around the command to get the feel for word motions.
+$ # Move cursor using begin ('Ctrl' + 'A') and end ('Ctrl' + 'E')
+$ # motions to the beginning and the end of the line.
+$ mkdir linux-practical-02 # Based on the previous command + motions.
+$ cd lin # TAB to complete, then TAB two times to list possible endings.
+$ cd linux-practical-02 # Based on the previous completion.
+$ # Move up the history list to mkdir subdir-01
+$ mkdir subdir-02
+$ # Move up the history to the touch subdir-01/a ... command.
+$ # Replace 1 with 2 using 'Ctrl' + 'A' and word motions.
+$ touch subdir-02/a subdir-02/b subdir-02/c
+$ history 10 # Lists last ten commands.
+$ cd
+```
+
+<!-- * Motions -->
+<!-- - `Left` and `Right` arrow move one character left, or right -->
+<!-- - `Ctrl` + `Left`, or `Right` move left, or right for one word -->
+<!-- - `Ctrl` + `A`, or `E` move to the beginning, or the end of the line -->
+<!-- - `Up` and `Down` move through history entries -->
+<!-- - `TAB` completes -->
+
+
+
+
+
+
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/shell/rm.md b/2020/2020-02-15_gnuLinuxCourse/slides/shell/rm.md
new file mode 100644
index 0000000000000000000000000000000000000000..348794912ce36a429fc8e5c8b116a220f07e3f82
--- /dev/null
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/shell/rm.md
@@ -0,0 +1,15 @@
+# File Explorer: Copy(cp), Move(mv) and Remove(rm) File Operations
+
+* Removing files and directories.
+
+```console
+$ rm linux-practical-03/pr3-hello-world.txt # Deletes the file.
+$ # History, one up then adapt the command into
+$ cd linux-practical-03
+$ ls # Check if it is indeed deleted.
+$ rm -R dump2 # Recursively remove directory dump2 and all of its contents.
+$ history 10 # Just to remind yourself what you did in last ten steps.
+$ cd
+
+```
+
diff --git a/2020/2020-02-15_gnuLinuxCourse/slides/shell/start.md b/2020/2020-02-15_gnuLinuxCourse/slides/shell/start.md
new file mode 100644
index 0000000000000000000000000000000000000000..1321b4f48f2d88ade8059685ccfee626cecdfb49
--- /dev/null
+++ b/2020/2020-02-15_gnuLinuxCourse/slides/shell/start.md
@@ -0,0 +1,36 @@
+# File Explorer: The Immediate Surroundings
+
+* Command line
+ - **Command prompt:** Non-editable; May provide contextual information
+ - **Command area:** Typed commands are shown here
+ - **RETURN or ENTER:** Pressing this key will execute the command
+ ```shell
+ prompt$ command arg1 arg2 ...
+ ```
+
+<!-- .element: class="fragment" -->
+ ```console
+ $ pwd # Displays the absolute path to the current dirrectory.
+ $ ls # List contents of the current directory.
+ $ mkdir linux-practical-01 # Create a new directory.
+ $ cd linux-practical-01 # Switch to a different directory.
+ $ touch pr1-hello-world.txt # Create a new and empty file.
+ $ mkdir subdir-01 # Create another directory.
+ $ touch subdir-01/a subdir-01/b subdir-01/c # Create multiple empty files.
+ $ ls subdir-01 # List contents of directory.
+ $ mkdir -p subdir-02/dir-X/dir-Y/dir-Z # Create a nested directory under the path.
+ $ ls subdir-02/dir-X # Confirm the directory dir-Y has been created.
+ $ history # Lists the commands executed so far.
+ $ cd
+ ```
+<!-- .element: class="fragment" -->
+
+<!-- * Concepts -->
+<!-- - Files and directories -->
+<!-- - Paths -->
+<!-- - Importance of quoting -->
+<!-- - History -->
+
+
+
+
diff --git a/2020/2020-02-15_gnuLinuxCourse/variae/figs/shell/3270.jpg b/2020/2020-02-15_gnuLinuxCourse/variae/figs/shell/3270.jpg
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