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Writing Your First Bash Script

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Writing Your First Bash Script: A Beginner’s Guide

Entering the world of Linux Bash scripting is an empowering experience. It opens up a new realm of possibilities, enabling you to automate tasks, streamline processes, and much more. If you are just getting started with Bash scripting, this guide is designed to introduce you to the basics and guide you through writing your first Bash script.

What is Bash Scripting?

Bash (Bourne Again SHell) is a shell and scripting language that is widely available on various Unix-like operating systems, including Linux and macOS. Bash scripting allows you to automate commands that you would otherwise have to type manually.

Setting Up Your System

Before writing your first script, make sure Bash is installed on your system. As Bash is the default shell for Linux and macOS, most users will find it pre-installed. Windows users can access Bash through the Windows Subsystem for Linux (WSL).

Installing Bash (if required)

For Linux users on distributions that might require Bash to be explicitly installed or upgraded, here are the instructions based on the package manager.

  1. APT (for Debian-based distros like Ubuntu):

    sudo apt update
sudo apt install bash

  2. DNF (for RPM-based distros like Fedora):

    sudo dnf check-update
sudo dnf install bash

  3. ZYPPER (for SUSE-based distros):

    sudo zypper refresh
sudo zypper install bash

Writing Your First Bash Script

Step 1: Create Your Script File

Open a terminal, then type the following command to create a new file:

touch my_first_script.sh

Step 2: Make the Script Executable

To execute your script, you must first make it executable with the following command:

chmod +x my_first_script.sh

Step 3: Writing the Script

Use your favorite text editor to open the file:

nano my_first_script.sh

Inside the script, type the following:

#!/bin/bash
# This is a simple Bash script

echo "Hello World!"

Here’s what each part means:

  • #!/bin/bash: This is called the shebang. It tells the system this file should be run in the Bash shell.

  • #: Lines starting with a hash symbol are comments. These lines are not executed.

  • echo: This is a command that prints out the text inside the quotes.

Save and close the file (CTRL+X followed by Y and then Enter in Nano).

Step 4: Running Your Script

To run your script, you can do so by calling it directly with:

./my_first_script.sh

If everything is set up correctly, the terminal will display:

Hello World!

Congratulations!

You’ve just written and executed your first Bash script! This is just the tip of the iceberg. Bash scripting is a powerful skill that can greatly enhance your control over Linux-based systems.

Going Further

To deepen your knowledge in Bash scripting:

  • Explore conditional statements like if-else.

  • Learn about loop structures such as for and while loops.

  • Manipulate file directories and contents with mkdir, rm, etc.

  • Dive into error handling to make your scripts more robust.

As you become more familiar with scripting, you will begin to see many opportunities to use Bash scripts to make your interaction with the operating system more efficient and even automated. Happy scripting!

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