Git fundamentals: commits, history, and branches · 第 2 / 5 节

Lesson 2: Start a repo and make your first commit

Lesson objectives:

Initialize a Git repository with git init.

Tell Git who you are with git config.

Stage a file with git add and save a snapshot with git commit.

Prerequisites: Lesson 01 (why Git exists, save points for files) | Previous << 01 | Next 03 >>

From folder to time machine

In the last lesson, a repository was a folder Git is watching. This lesson makes that real. You will create a folder, turn it into a repository, and save your first snapshot.

Git keeps its history in a hidden .git directory inside your folder. You do not need to open it; you just need to know it exists. When you run git init, Git creates that directory and the folder becomes a repository ¹.

Before you can commit, Git needs to know your name and email address. It writes this information into every commit so you know who made each change later ².

The three-area model, simplified

Git thinks of your files in three places at once:

Working directory — the files you see and edit in your folder.
Staging area — a temporary holding spot for changes you want to commit next.
Repository — the permanent history of commits ³.

The command git add <file> copies a file from the working directory into the staging area. The command git commit takes everything in the staging area and records it as a new commit ².

The diagram shows the direction of the two main commands: git add moves changes into the staging area, and git commit moves them into the history.

Worked example (follow along)

Open your terminal and run these commands exactly. They will create a safe practice folder on your Desktop.

BASH

# 1. Make a practice folder and enter it
mkdir -p ~/Desktop/git-practice
cd ~/Desktop/git-practice

# 2. Turn it into a Git repository
git init

# 3. Tell Git who you are (use your own name and email)
git config user.name "Asha Smith"
git config user.email "asha@example.com"

# 4. Create a file and write something in it
echo "My first tracked file" > draft.txt

# 5. Stage the file
git add draft.txt

# 6. Save a snapshot with a short message
git commit -m "Add first draft"

If everything worked, the last line should show something like 1 file changed, 1 insertion(+) and a commit hash. That hash is the unique ID of your new commit.

Your turn (faded example)

Here is the same sequence with two blanks. Fill them in with the commands you just learned.

BASH

git init
--- your name here ---
--- your email here ---
echo "Practice line" > notes.txt
git add notes.txt
git commit -m "Add practice notes"

Answer:

BASH

git config user.name "Your Name"
git config user.email "you@example.com"

Summary + what's next

You turned a folder into a repository, set your name and email, and saved your first commit. You now know the difference between the working directory, staging area, and repository history. In the next lesson, you will read that history and recover an older version of a file.

Pro Git, Getting a Git Repository — https://git-scm.com/book/en/v2/Git-Basics-Getting-a-Git-Repository ↩
Pro Git, Recording Changes to the Repository — https://git-scm.com/book/en/v2/Git-Basics-Recording-Changes-to-the-Repository ↩ ↩²
Pro Git, What is Git? — https://git-scm.com/book/en/v2/Getting-Started-What-is-Git%3F ↩

练习

Create a folder called git-practice on your Desktop, run git init, then type git status.

Level 1 (warm-up)

完成标准 · 本地勾选

`git init` prints a message like `Initialized empty Git repository in .../git-practice/.git/`.`git status` shows `On branch main` (or `master`) and `No commits yet`.You can see a new `.git` folder exists inside `git-practice`.

Inside the same git-practice folder, create a text file, stage it, and commit it. Use a commit message that says what you changed.

Level 2 (advanced)

完成标准 · 本地勾选

You have created a file with a few lines of text.`git add <filename>` runs without error.`git commit -m "..."` prints output showing `1 file changed` and a commit hash.`git status` afterward shows `nothing to commit, working tree clean`.

Lesson 2: Start a repo and make your first commit

From folder to time machine

The three-area model, simplified

Worked example (follow along)

Your turn (faded example)

Summary + what's next

Footnotes

练习

Create a folder called git-practice on your Desktop, run git init, then type git status.

Inside the same git-practice folder, create a text file, stage it, and commit it. Use a commit message that says what you changed.