Introduction to Scripting

What is Scripting?

Scripting refers to the automation of tasks through the use of scripts. A script is a series of commands that are executed without user interaction. Scripting languages are often interpreted, meaning they are executed directly without the need for compilation.

Why Use Scripting?

Scripting can save time and reduce errors by automating repetitive tasks. It allows for the quick creation of tools and utilities, and can help in managing system configurations and deployments.

Common Scripting Languages

Some of the most common scripting languages include:

• Python
• Bash
• Perl
• Ruby

Basic Script Structure

A basic script typically consists of a series of commands or statements. Here is an example of a simple Bash script:

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

Let's break down this script:

• #!/bin/bash: This is called a shebang. It tells the system that the script should be run using the Bash shell.
• echo "Hello, World!": This command prints "Hello, World!" to the terminal.

Running a Script

To run a script, you need to make it executable and then execute it. Here are the steps:

chmod +x script_name.sh
./script_name.sh

Explanation:

• chmod +x script_name.sh: This command makes the script executable.
• ./script_name.sh: This command runs the script.

Variables in Scripting

Variables are used to store data that can be used later in the script. Here is an example of a Bash script using variables:

#!/bin/bash
name="John"
echo "Hello, $name!"

Explanation:

• name="John": This command assigns the value "John" to the variable name.
• echo "Hello, $name!": This command prints "Hello, John!" to the terminal by using the value of the name variable.

Conditional Statements

Conditional statements are used to perform different actions based on different conditions. Here is an example of an if statement in Bash:

#!/bin/bash
if [ "$name" == "John" ]; then
    echo "Your name is John."
else
    echo "Your name is not John."
fi

Explanation:

• if [ "$name" == "John" ]; then: This line checks if the value of name is "John".
• echo "Your name is John.": This line is executed if the condition is true.
• else: This starts the section of code that will run if the condition is false.
• echo "Your name is not John.": This line is executed if the condition is false.
• fi: This ends the if statement.

Loops

Loops are used to repeat a block of code multiple times. Here is an example of a for loop in Bash:

#!/bin/bash
for i in {1..5}; do
    echo "Iteration $i"
done

Explanation:

• for i in {1..5}; do: This line starts a loop that will iterate from 1 to 5.
• echo "Iteration $i": This line is executed in each iteration of the loop, printing the current iteration number.
• done: This ends the loop.