Chapter 7: Shell Scripting Basics in WSL Ubuntu (Automate with Bash)

Once you’re comfortable using Linux commands, it’s time to automate them. That’s where shell scripting comes in. In WSL Ubuntu, you can write Bash scripts to execute multiple commands automatically.

Shell scripts are used for everything from simple file backups to automated server setups. This chapter will show you how to write your first shell scripts step by step.

📜 What Is a Shell Script?

A shell script is a plain text file containing a series of Linux commands. Instead of typing each command manually, you save them in a file and run them all at once.

🧾 Create Your First Shell Script

📌 Step 1: Create a New File

nano hello.sh

📌 Step 2: Add This Code

#!/bin/bash

echo "Hello, $USER!"
echo "Today is $(date)"
echo "Your current directory is: $(pwd)"

📌 Step 3: Save and Exit

In nano, press:

Ctrl + O → Enter → Ctrl + X

📌 Step 4: Make It Executable

chmod +x hello.sh

📌 Step 5: Run the Script

./hello.sh

🎉 You’ve just run your first Bash script!

📌 Script Structure Explained

• #!/bin/bash – Shebang line tells Linux to use Bash
• echo – Prints messages
• $(command) – Runs command and substitutes output
• $USER – Current user
• $(date) – Current date and time

📂 More Useful Commands in Scripts

ls -la
mkdir backup
cp *.txt backup/
df -h

You can include any Linux command in a shell script.

🧠 Using Variables

#!/bin/bash

name="Umar"
echo "Welcome, $name"

🔁 Adding Loops

#!/bin/bash

for file in *.txt
do
  echo "Copying $file"
  cp "$file" backup/
done

❓ Adding Conditions

#!/bin/bash

if [ -d "backup" ]; then
  echo "Backup folder exists"
else
  echo "Creating backup folder..."
  mkdir backup
fi

🧪 Practice Challenge

Create a script named myscript.sh that:

• Greets the user
• Displays today’s date
• Creates a folder called mybackup if it doesn’t exist
• Copies all .log files into mybackup

#!/bin/bash

echo "Hi $USER, welcome back!"
echo "Today is $(date)"

if [ ! -d "mybackup" ]; then
  mkdir mybackup
fi

cp *.log mybackup/

✅ Summary

• Shell scripts are simple text files with Linux commands
• Use #!/bin/bash at the top
• Make scripts executable with chmod +x
• You can use variables, conditions, and loops
• Automate repetitive tasks with ease!

▶️ Coming Up Next

Chapter 8 – Networking Basics in WSL Ubuntu
Learn how to use commands like ping, ip, netstat, and check connectivity from WSL.