What is Shell Script?

What is a shell script?

A shell script is a text file that contains a sequence of commands for a Unix or Linux shell to execute. Instead of typing commands one by one, you write them in a file and run them all at once.

How shell scripts work

Shell scripts are interpreted by a shell program such as Bash. When you run the script, the shell reads each line and executes it in order.

Basic shell script example

#!/bin/bash

echo "Hello, World!"
echo "This is a shell script"

The first line (#!/bin/bash) tells the system to use the Bash shell to run the script.

Why use shell scripts?

• ⚡ Automate repetitive tasks
• 🖥️ Manage files and system operations
• ⏱️ Save time in development and administration
• 🔧 Run multiple commands with one execution

Common uses of shell scripts

• 📁 File backup and cleanup
• 🚀 Deploying applications
• 🛠️ System monitoring
• 📦 Installing software packages

Variables in shell scripts

name="Alice"

echo "Hello $name"

Conditional statements

if [ 10 -gt 5 ]
then
  echo "10 is greater than 5"
fi

Loops in shell scripting

for i in 1 2 3
do
  echo "Number: $i"
done

Summary

A shell script is a file containing Linux commands that automate tasks. It is widely used for system administration, development workflows, and automation.

In short: Shell scripts let you control your computer with reusable command sequences.