Shell scripting is a powerful way to automate tasks in a Linux environment. It allows you to write scripts that can execute commands, manage files, and perform complex operations without manual intervention. This module will introduce you to the basics of shell scripting, including writing and executing simple scripts.

A shell script is a text file containing a sequence of commands for a Unix-based operating system's shell to execute. Shell scripts can automate repetitive tasks, manage system operations, and even perform complex programming tasks.

• Shell: The command-line interface that interprets and executes user commands.
• Script: A file containing a series of commands that the shell can execute.

• Automation: Automate repetitive tasks to save time and reduce errors.
• Efficiency: Perform complex operations with a single script.
• Customization: Tailor scripts to meet specific needs and workflows.
• Integration: Combine multiple commands and tools to create powerful workflows.

1. Create a New File: Use a text editor to create a new file. Name it first_script.sh.
2. Add the Shebang Line: The first line of a shell script should be the shebang (#!) followed by the path to the shell interpreter.

   #!/bin/bash
   

3. Write Commands: Add the commands you want to execute. For example:

   #!/bin/bash
   echo "Hello, World!"
   

4. Save the File: Save the file and exit the text editor.
5. Make the Script Executable: Use the chmod command to make the script executable.

   chmod +x first_script.sh
   

6. Run the Script: Execute the script by typing ./first_script.sh in the terminal.

   ./first_script.sh
   

• #!/bin/bash: Specifies the script should be run using the Bash shell.
• echo "Hello, World!": Prints "Hello, World!" to the terminal.
• echo "Welcome to shell scripting!": Prints "Welcome to shell scripting!" to the terminal.

Create a shell script named greet_user.sh that:

1. Prompts the user for their name.
2. Greets the user with a personalized message.

1. Create the Script File:

   nano greet_user.sh
   

2. Add the Shebang Line and Commands:

   #!/bin/bash
   # Script to greet the user
   
   echo "Please enter your name:"
   read name
   echo "Hello, $name! Welcome to shell scripting!"
   

3. Save and Exit: Save the file and exit the text editor.
4. Make the Script Executable:

   chmod +x greet_user.sh
   

5. Run the Script:

   ./greet_user.sh
   

• read name: Reads input from the user and stores it in the variable name.
• echo "Hello, $name! Welcome to shell scripting!": Uses the variable name to print a personalized greeting.

• Forgetting the Shebang Line: Always start your script with #!/bin/bash to ensure it runs with the correct shell.
• File Permissions: Remember to use chmod +x to make your script executable.
• Syntax Errors: Double-check your syntax, especially for commands and variable usage.

In this lesson, you learned the basics of shell scripting, including writing and executing a simple script. Shell scripting is a powerful tool for automating tasks and managing your Linux environment efficiently. In the next lesson, we will dive deeper into variables and data types in shell scripting.