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Chapter 4: The Conditional Conundrums 🤔

1 - The What, Why and Types of conditionals in linux

Understanding Conditionals in Linux Shell Scripting

What are Conditionals in Linux?

Conditionals in Linux shell scripting are constructs that allow the execution of different commands or actions based on specified conditions. These conditions evaluate to true or false, and based on the result, the shell script executes different code paths. Conditionals enable the script to make decisions and control the flow of execution, enhancing the script's flexibility and functionality.

Why Use Conditionals?

Conditionals are essential in shell scripting for performing tasks such as error handling, data validation, and decision-making based on user input or system conditions. They allow scripts to respond dynamically to changing circumstances, improving their adaptability and robustness. By incorporating conditionals, shell scripts can automate complex logic and perform tasks efficiently based on predefined conditions.

Types of Conditionals in Linux Shell Scripting

There are primarily two types of conditionals used in Linux shell scripting:

1. if Statements:

if statements allow you to execute a block of code if a specified condition is true. They can also include optional elif (else if) and else clauses to handle multiple conditions.

Example:

#!/bin/bash

# Check if a number is greater than 10
number=15
if [ $number -gt 10 ]; then
    echo "The number is greater than 10."
else
    echo "The number is not greater than 10."
fi

2. case Statements:

case statements provide a way to perform multiple conditional checks in a more structured and concise manner. They evaluate a variable against a list of patterns and execute corresponding code blocks for matching patterns.

#!/bin/bash

# Check the day of the week
day="Monday"
case $day in
    Monday)
        echo "Today is Monday."
        ;;
    Tuesday|Wednesday|Thursday|Friday)
        echo "It's a weekday."
        ;;
    Saturday|Sunday)
        echo "It's a weekend."
        ;;
    *)
        echo "Invalid day."
        ;;
esac

Conclusion

These conditionals form the backbone of decision-making in Linux shell scripts, allowing you to create versatile and powerful scripts that respond intelligently to different scenarios.

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