---
description: >-
  In this post, I delve into the Linux Shells module from TryHackMe’s Cyber
  Security 101 learning path. This module offers a comprehensive introduction to
  Linux command-line interfaces, shell scripting,
---

# Mastering Linux Shells : A TryHackMe Walkthrough

## Module Overview

The module covers:

* **Understanding Shells**: The interface between the user and the operating system.
* **Interacting with the Shell**: Basic commands and navigation.
* **Types of Linux Shells**: Exploring different shells like Bash, Zsh, and Fish.
* **Shell Scripting**: Writing and executing shell scripts.
* **Practical Exercises**: Hands-on tasks to apply learned concepts.

### 🛠️ Key Scripts from the Module

#### 1. The Locker Script

This script simulates a bank locker authentication system, prompting the user for their username, company name, and PIN. If the provided credentials match predefined values, access is granted.

```
#!/bin/bash

# Defining the variables
username=""
companyname=""
pin=""

# Defining the loop
for i in {1..3}; do
    # Defining the conditional statements
    if [ "$i" -eq 1 ]; then
        echo "Enter your Username:"
        read username
    elif [ "$i" -eq 2 ]; then
        echo "Enter your Company name:"
        read companyname
    else
        echo "Enter your PIN:"
        read pin
    fi
done

# Checking if the user entered the correct details
if [ "$username" = "John" ] && [ "$companyname" = "Tryhackme" ] && [ "$pin" = "7385" ]; then
    echo "Authentication Successful. You can now access your locker, John."
else
    echo "Authentication Denied!!"
fi

Note: Ensure you're executing it with Bash and not sh.
```

1. The Flag Hunt Script This script searches for a specific flag within system logs, demonstrating the use of grep and find commands.

## &#x20;**Practical Exercises**

&#x20;The module includes exercises like:

* The Locker Script: A script that authenticates users based on predefined credentials.
* Flag Hunt: Searching for a specific flag within system logs.

## **🔗 Repository Overview**

[<mark style="color:orange;">**REPOSITORY**</mark>](https://github.com/Vinayjango101/THM-LinuxShells)

&#x20;**I’ve documented all the scripts and exercises from this module in my GitHub repository: THM-LinuxShells. The repository includes:**

* lockerscript.sh: The authentication script.
* flag\_hunt.sh: The script for searching flags in logs.
* shell.sh and shell2.sh: Additional shell scripting exercises.

**Conclusion The Linux Shells module is an excellent starting point for anyone looking to understand Linux command-line operations and scripting. The hands-on exercises provide practical experience, reinforcing the concepts learned.**

Feel free to explore the repository and try out the scripts. Happy learning!
