I made my own version of Git using Python as a way to learn about terminal and file management in python (os, sys), hashing, and connecting URLs in Python. I also developed a deeper understanding of version history management with Git (hashing, compressing, etc.).

Depending on your OS, run:

python3 {path to main.py} command_name parameter(s)

or

python {path to main.py} command_name parameter(s)

(Terminal input is prefixed with $. It assumes that your current directory has the main.py file.)
(Comments are prefixed with #, like Python syntax.)
(Output has no prefix.)

$ python3 main.py init
git initialised!

Parameters implemented: None
Description: Initializes a Git repository by creating a .git directory with some files & directories inside it.

$ python3 main.py cat-file -p <blob_sha1_hash>
hello world # This is the contents of the blob

Parameters implemented: -p <blob_sha1_hash> (compulsory)
Description: Used to view the type of an object, its size, and its content. (Works only for blob objects.)

$ python3 main.py hash-object -w test.txt
95d09f2b10159347eece71399a7e2e907ea3df4f # This is the SHA1 hash of the blob (content of file stored in .git/objects/95/d09f2b10159347eece71399a7e2e907ea3df4f)

Parameters implemented: -w (writes the blob to .git/objects)
Description: Used to compute the SHA1 hash of a Git blob.

$ python3 main.py ls-tree <tree_sha>
040000 tree <tree_sha_1>    dir1
040000 tree <tree_sha_2>    dir2
100644 blob <blob_sha_1>    file1

Parameters implemented: --name-only (only outputs names of files and folders)

Example:

$ python3 main.py ls-tree --name-only <tree_sha>
dir1
dir2
file1

Description: Used to inspect a tree object.

$ python3 main.py write-tree # Assumes all changes are staged in the current working directory
4b825dc642cb6eb9a060e54bf8d69288fbee4904 # Returns SHA1 hash of the tree object

Parameters implemented: None
Description: Creates a tree object from the current state of the "staging area".
I did not implement a staging area in my code and will assume that all files in the working directory are staged.

$ python3 main.py commit-tree <tree_sha> -p <commit_sha> -m <message>

Parameters implemented:

• -p <parent_sha> (optional; stores the commit object under .git/objects/parents_sha/ instead of .git/objects/)
• -m (includes message in commit)

Description: Creates a commit object and prints its 40-character SHA to stdout.

$ python3 main.py clone https://github.com/blah/blah <some_dir>

Parameters implemented: None
Description: Creates <some_dir> and clones the given repository into it given the GitHub URL.