Bash Introduction & Setup – What Is Bash, Shell Comparison & Installation Guide

Introduction – Why Learn Bash?

Ever wonder how system admins automate tasks, manage servers, or write backup routines without ever touching a mouse? That magic often comes from Bash. Bash is the default command-line shell that comes pre-installed on most Linux distributions and macOS systems. Whether you’re writing your first shell script or deploying containers, Bash is the tool that ties it all together.

In this guide, you’ll learn:

• An overview of Bash and how it compares to other widely used shells.
• How to check your current Bash version
• Steps to install or update Bash on Linux, macOS, and Windows
• Major distinctions between Bash, Zsh, and Fish shells

Topics Covered

What is Bash?

Bash stands for Bourne Again SHell—a modern replacement for the original sh shell. It’s the default shell on almost all Linux distributions and older versions of macOS.

Key Features:

• Remembers your command history
• Allows script automation using .sh files
• Supports input/output redirection and piping
• Provides job control, aliases, variables, and more

Bash is essential for DevOps engineers, system administrators, and even hobbyists working with Linux or macOS.

What is a Shell?

A shell is a command interpreter—it takes what you type and passes it to the operating system. Without a shell, there’s no way to talk to your OS using text commands.

Types of Popular Shells:

Bash is POSIX-compliant, meaning it works across a wide variety of Unix-like systems.

Bash vs Other Shells (Zsh, Fish)

Not all shells are created equal. Let’s break down the differences.

Bash vs Zsh

Zsh is flashier, but Bash is still the scripting king.

Bash vs Fish

Fish is friendly for interactive use but not great for portable scripts.

Check Your Bash Version

Want to know if your Bash is outdated? Here’s how:

bash --version

Sample Output:

GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)

This tells you you’re running Bash 5.1.16.

How to Install or Upgrade Bash

Now that you understand Bash’s importance, let’s get it installed or updated based on your OS.

On Ubuntu/Debian-based systems:

sudo apt update
sudo apt install bash

This ensures Bash is installed or upgraded to the latest version available from APT.

On CentOS/RHEL-based systems:

sudo yum install bash

This will install Bash via the YUM package manager.

On macOS (Install Bash 5+ via Homebrew):

macOS comes with Bash 3.x pre-installed due to licensing restrictions. You can install Bash 5 using Homebrew:

brew install bash

Then, make it your default login shell:

sudo bash -c 'echo /usr/local/bin/bash >> /etc/shells'
chsh -s /usr/local/bin/bash

This step lets you use the newer Bash shell system-wide.

On Windows (via WSL):

To use real Bash on Windows, install the Windows Subsystem for Linux (WSL):

wsl --install

This installs a full Linux environment (like Ubuntu) with Bash included.

Other Windows Options:

If you don’t want to use WSL, try:

• Git Bash: Comes bundled with Git for Windows
• Cygwin: Offers a Linux-like environment

Summary: Bash Introduction & Setup

Bash is your gateway to mastering the command line. From automating scripts to controlling servers, it’s a foundational skill every developer or admin should learn.

Key Takeaways:

• Bash is the default shell for Linux and macOS
• It’s POSIX-compliant and ideal for scripting
• Zsh and Fish offer alternatives but with tradeoffs
• Bash can be installed on any major OS, including Windows via WSL

Real-World Applications:

• Automate backup or deployment scripts
• Control Docker containers
• Configure cron jobs
• Monitor system performance using shell commands

FAQ: Bash Introduction & Setup

Is Bash the same as the Linux terminal?
No. The terminal is the interface (like GNOME Terminal), and Bash is the shell that runs inside it.

Can I replace Bash with Zsh or Fish?
Yes. However, Bash is more universally compatible—especially for scripts shared across systems.

How do I know if I’m using Bash?
Run the following command:

echo $SHELL

If it returns /bin/bash or similar, you’re using Bash.

What’s the latest version of Bash?
As of now, the latest release is Bash 5.2.x. Visit the GNU Bash Releases page for updates.

Can I use Bash on Windows without WSL?
Yes. Tools like Git Bash and Cygwin simulate Bash behavior, though they’re not full Unix environments.