feat: replace with a mini exercise (#8509)

Adding a mini exercise about bash scripting

src/data/roadmaps/linux/content/shell-basics/index.md

@@ -4,8 +4,10 @@ The Linux shell is a command-line interface or terminal used to interact directl
 
 The basics of using a Linux shell include navigating between directories, creating, renaming and deleting files and directories, and executing system commands. This introductory level knowledge is crucial for Linux system administration, scripting, and automation.
 
-Here is a classic `bash` command as an example, which prints the current directory:
+This is a follow up exercise to make your first bash script. Please run the commands in the terminal one by one and try to understand what they do:
-
+```
-```bash
+touch my_first_script.sh
-pwd
+chmod +x my_first_script.sh
+echo "date" > my_first_script.sh
+./my_first_script.sh
 ```