1. Project Goal and Demonstrated Insight Goal: To implement a basic Git clone operation entirely within a shell script, accurately following the Git Smart HTTP Protocol (Git's network protocol). Insight Demonstrated: This project required understanding and handling the complexities of a binary application-layer network protocol. Specifically, it demonstrates mastery over:

• Binary Protocol Parsing: Sending raw HTTP requests and correctly interpreting the structure of the Git \mathbf{pkt-line} (packet-line) format in the server's binary response.
• Data Extraction: Developing robust \mathbf{regular\ expressions} to accurately locate and extract critical 40-character \mathbf{SHA-1\ hashes} from the noisy protocol data stream.
• Low-Level System Integration: Orchestrating core Linux utilities (curl, grep, printf, etc.) and Git internals (git unpack-objects) to successfully download and reconstruct the complete repository structure.

1. Final Script Code The final production script, mygitcloneperfected.sh (or mygitcloneproduction.sh), is omitted for brevity but is submitted separately. The script successfully handles initialization, capability discovery, hash extraction, packfile negotiation, and object unpacking.
2. Demonstration Log: Successful Repository Clone The following log confirms the successful cloning of a public Git repository. A. Execution of the Clone Command $ ./mygitcloneperfected.sh clone https://github.com/octocat/Hello-World codecrafterstest Repository: octocat/Hello-World Target directory: codecrafterstest === Git Clone Implementation === Cloning into 'codecrafterstest'… Working in: /data/data/com.termux/files/home/codecrafterstest Step 1: Initializing git directory… Git directory initialized Step 2: Discovering server capabilities… Fetching from: https://github.com/octocat/Hello-World.git/info/refs?service=git-upload-pack Binary response received: 142733 bytes Step 3: Extracting master branch hash… Searching for master branch reference… Found master line: 003f7fd1a60b01f91b314f59955a4e4d4e80d8edf11d refs/heads/master Master branch hash: 7fd1a60b01f91b314f59955a4e4d4e80d8edf11d Step 4: Preparing negotiation request… Using master branch hash: 7fd1a60b01f91b314f59955a4e4d4e80d8edf11d Binary request prepared: 63 bytes Step 5: Downloading packfile… POST to: https://github.com/octocat/Hello-World.git/git-upload-pack Response received: 708 bytes Found packfile at offset: 8 Packfile extracted: 700 bytes Packfile signature verified Step 6: Unpacking objects… Objects unpacked successfully: 7 objects Step 7: Checking out files… Checking out master branch: 7fd1a60b01f91b314f59955a4e4d4e80d8edf11d Checkout completed successfully Step 8: Cleaning up temporary files… === Clone completed successfully! === Repository: codecrafterstest Branch: master

B. Verification of Cloned Repository Integrity The verification steps confirm that the cloned directory is a fully functioning Git repository, complete with the correct file content and commit history. $ cd codecrafters_test

1. Verify File Content

$ cat README Hello World!

2. Verify Git History (Must match the remote repository's history)

$ git log --oneline 7fd1a60 (HEAD, master) Merge pull request #6 from Spaceghost/patch-1 7629413 New line at end of file. --Signed off by Spaceghost 553c207 first commit

4. Error Handling Demonstration (Robustness) The script includes necessary error handling to check HTTP status codes, preventing execution failures when a repository is inaccessible or non-existent.

Test with a non-existent repository (simulating a 401 or 404 error)

$ ./mygitcloneproduction.sh clone https://github.com/user/repo testnonexistent Repository: user/repo … Step 2: Discovering server capabilities… Fetching from: https://github.com/user/repo.git/info/refs?service=git-upload-pack Response received: 21 bytes (HTTP 401) Error: Failed to access repository (HTTP 401) Server message: [… Error message correctly extracted from minimal response …]