diff --git a/2021/2021-03-18_basicGitTraining/slides/best_practices.md b/2021/2021-03-18_basicGitTraining/slides/best_practices.md
index 6bc6084c1b40fbf6669a1c9c7b2113437ba3a786..815cc80fb0980e3419ae6e00887707c14de3d02c 100644
--- a/2021/2021-03-18_basicGitTraining/slides/best_practices.md
+++ b/2021/2021-03-18_basicGitTraining/slides/best_practices.md
@@ -1,6 +1,6 @@
 # Best practices
 
-* `pull` before `push`
+* `pull` before `push` and, generally, before starting to work
 * Work on your <font color="red">own</font> branch (in your own fork), and **not** on `master` and **not** on `develop`
 * Do **not push** to `master`, but **submit a Pull Request (PR)**
 * Get your code **reviewed** by your peers (submit a PR!)
diff --git a/2021/2021-03-18_basicGitTraining/slides/configuration.md b/2021/2021-03-18_basicGitTraining/slides/configuration.md
index 6217c28d6a1e061695cc8ca48f250ea6c449d6d0..39ca62da5a8aa6b9c63835c07fe8e48905a173b5 100644
--- a/2021/2021-03-18_basicGitTraining/slides/configuration.md
+++ b/2021/2021-03-18_basicGitTraining/slides/configuration.md
@@ -38,7 +38,7 @@ If there are 2 files named `id_rsa`, you have an SSH key.
 
 If you don’t have yet an SSH key, you have to generate one:
 ```bash
-$ ssh-keygen -t rsa # -b 4096
+$ ssh-keygen -t rsa -b 4096
 ```
 
 If you set a password to your key (recommended), add it to the `ssh-agent`:
diff --git a/2021/2021-03-18_basicGitTraining/slides/essential_commands.md b/2021/2021-03-18_basicGitTraining/slides/essential_commands.md
index 8e1e0f643a6df3ed7a3099381c616d70b919faca..982f1a4e4c550a0471c23609971e6a49ac13c596 100644
--- a/2021/2021-03-18_basicGitTraining/slides/essential_commands.md
+++ b/2021/2021-03-18_basicGitTraining/slides/essential_commands.md
@@ -45,6 +45,9 @@ $ cp firstnameLastname.md myName.md
 
 Then, make your changes with your favorite editor!
 
+<br><br>
+Reference for markdown: https://howto.lcsb.uni.lu/?contribute:markdown
+
 
 
 # Add your file to the stage
@@ -71,7 +74,11 @@ $ git status
 ```bash
 $ git diff
 ```
-exit with `q`
+exit with `q`.
+
+<br>
+
+![bulb](slides/img/bulb.png)  If it is a long diff, you can display additional lines with space.
 
 
 
diff --git a/2021/2021-03-18_basicGitTraining/slides/the_terminal.md b/2021/2021-03-18_basicGitTraining/slides/the_terminal.md
index 0abe54183778dc4ff637384cc65fedfc0fdc147a..7d08c2402068899c85a50d01685e625081445eba 100644
--- a/2021/2021-03-18_basicGitTraining/slides/the_terminal.md
+++ b/2021/2021-03-18_basicGitTraining/slides/the_terminal.md
@@ -28,7 +28,12 @@ $ git --version
 
 List the contents of a directory
 ```bash
-$ ls #-lash
+$ ls
+```
+
+You can list more details with:
+```bash
+$ ls -lah
 ```
 
 Create a directory
@@ -36,6 +41,8 @@ Create a directory
 $ mkdir myNewDirectory
 ```
 
+
+
 Change the directory to a specific folder
 ```bash
 $ cd myNewDirectory
@@ -50,8 +57,6 @@ $ cd ../..
 # 2 levels up
 ```
 
-
-
 Move a file or a directory
 ```bash
 $ mv myFile.m myNewDirectory/.