Useful Assignments

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Problem 1: Directory Cleanup Script

Write a Bash script that finds all files in a specified directory that are older than 30 days and deletes them. The script should prompt the user to confirm before proceeding with the deletion.

Requirements:

• Use command-line argument to specify the directory.

• Use find command to locate files older than 30 days.

• Ensure proper validation if the directory doesn’t exist.

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Problem 2: User Account Monitoring

Create a Bash script that monitors active user accounts on a Linux system. The script should:

• List all logged-in users.

• Write the output to a log file.

• Include a timestamp indicating when the report was generated.

Requirements:

• Use who or w to list active users.

• Append to a log file.

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Problem 3: File Backup Automation

Write a script that automatically backs up all files from the ~/Documents directory to a ~/backup/ directory. The script should create the backup directory if it doesn't exist and compress the files into a .tar.gz archive.

Requirements:

• Validate the existence of the source and destination directories.

• Include a timestamp in the backup file's name.

• Use tar to create a compressed archive.

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Problem 4: Simple Password Generator

Create a script that generates a random password. The password should include:

• At least one uppercase letter, one lowercase letter, one digit, and one special character.

• The script should prompt the user to input the desired password length.

Requirements:

• Use /dev/urandom or openssl rand.

• Perform input validation for length (minimum 8 characters).

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Problem 5: System Resource Usage Summary

Create a script that gathers and displays a summary of the system's resource usage, including:

• CPU usage

• Memory usage

• Disk space usage

• Top 5 CPU-consuming processes

Requirements:

• Use uptime, free -h, df -h, and ps.

• Display output in a readable format.

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Problem 6: Log File Analyzer

Write a script that accepts a log file as input and outputs the top 10 most frequent IP addresses found in the file. The script should handle input validation and check if the file exists.

Requirements:

• Use grep to search for IP addresses.

• Use sort and uniq to count occurrences.

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Problem 7: Process Killer

Create a script that lists all processes running on the system and prompts the user to select a process to kill based on the process ID (PID). The script should:

• Validate that the PID entered by the user is valid.

• Provide confirmation before killing the process.

Requirements:

• Use ps to list processes.

• Use kill to terminate the process.

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Problem 8: File Permission Checker

Write a script that checks the permissions of all files in a specified directory and lists files that are world-writable (chmod 777). The script should also give the option to change the permissions to chmod 644 for each file found.

Requirements:

• Use find to locate files with specific permissions.

• Use chmod to modify file permissions.

• Implement input validation and confirmation prompts.

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Problem 9: Port Scanner

Write a simple port scanner script that scans the first 1024 ports of a given IP address and reports which ports are open.

Requirements:

• Use nc (netcat) or nmap if available.

• Validate the IP address input.

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Problem 10: Directory Size Monitor

Create a script that monitors the size of a specified directory and notifies the user if it exceeds a certain threshold (e.g., 1GB). The script should run in the background and check the directory size every hour.

Requirements:

• Use du -sh to check directory size.

• Use sleep to add a time delay between checks.

• Send notifications using echo or write to a log file.

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Optional Challenge: Interactive Menu

Build a script that offers a menu with options to run any of the above problem scripts (or their solutions). The user should be able to select a script from the menu, run it, and return to the menu afterward.

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These assignments cover a range of topics, from file manipulation and process handling to system monitoring and security-related tasks. They help learners develop practical skills while reinforcing Bash scripting concepts. You can evaluate students based on their ability to:

1. Implement correct logic.

2. Handle input validation and error handling.

3. Write clear, maintainable code with comments.