5 Years Using Git Yet Still Missing the Basics? Master Core Git Operations

1. Installing and Configuring Git

Installation commands for common Linux distributions.

sudo apt update
sudo apt install git

sudo yum install git
# or on CentOS 8+
sudo dnf install git

Set the global user name and email, which are recorded with every commit.

git config --global user.name "张三"
git config --global user.email "[email protected]"

Example ~/.gitconfig that configures editor, file‑mode handling, performance tweaks, line‑ending conversion, color output, useful aliases, and credential helpers.

# ~/.gitconfig
[user]
    name = 张三
    email = [email protected]

[core]
    editor = vim
    filemode = false
    preloadindex = true
    fscache = true
    autocrlf = true

[color]
    ui = auto
[color "branch"]
    current = yellow reverse
    local = yellow
    remote = green
[color "diff"]
    meta = yellow bold
    frag = magenta bold
    old = red bold
    new = green bold
[color "status"]
    added = yellow
    changed = green
    untracked = cyan

[alias]
    lg = log --color --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit
    st = status
    df = diff
    dfc = diff --cached
    br = branch -a
    co = checkout
    cb = checkout -b
    unstage = reset HEAD --
    discard = checkout -- .
    last = log -1 HEAD
    show = show --stat

[pull]
    rebase = true

[push]
    default = simple

[merge]
    ff = only

[credential]
    helper = store

2. Core Working Model

Git operates on three areas.

Working Directory : files as they appear on the filesystem.

Staging Area (Index) : records which changes will be included in the next commit.

Repository : permanent storage of all commits.

Analogy: a room is the working directory, a box at the door is the staging area, and a moving truck is the repository. git add moves files to the box; git commit loads the box onto the truck.

Object storage – everything is a hash

Each object is identified by a 40‑character SHA‑1 hash. Four object types exist:

Blob : file contents.

Tree : directory structure and filenames.

Commit : metadata (author, timestamp, message) plus pointers to parent commit(s) and the root tree.

Tag : human‑readable label, often used for releases.

Branch representation

A branch is a plain text file under .git/refs/heads/ containing a single 40‑character hash that points to the tip commit of that branch.

3. Typical Development Workflow

Recommended sequence instead of a one‑liner git add . && git commit -m "msg" && git push:

Inspect changes:

git status
git diff

Selectively add to the index:

# single file
git add filename

# whole directory
git add directory/

# interactive, choose hunks
git add -p

Commit with a descriptive message:

git commit -m "Brief description of the logical change"

Push to the remote repository:

git push

The interactive git add -p helps avoid committing unintended files.

Commit‑history hygiene

One logical change per commit.

Each commit builds and runs.

Do not commit half‑finished work; use git stash if needed.

Before pushing, rewrite local history with git rebase -i to squash or reorder commits.

Branching strategies

Git Flow : suited for teams with fixed release cycles.

GitHub Flow : simpler, fits continuous deployment.

Selection depends on the team’s workflow requirements.

4. Git in CI/CD Pipelines

Push events trigger pipelines on platforms such as GitHub, GitLab, or Gitee. Configuration files ( .github/workflows/, .gitlab-ci.yml) define the steps.

Example: GitHub Actions for a Node.js project

# .github/workflows/ci.yml
name: CI/CD Pipeline

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'
      - name: Install dependencies
        run: npm ci
      - name: Lint code
        run: npm run lint
      - name: Run unit tests
        run: npm test
      - name: Build project
        run: npm run build

  deploy:
    needs: test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4
      - name: Deploy to server
        uses: appleboy/[email protected]
        with:
          host: ${{ secrets.SERVER_HOST }}
          username: ${{ secrets.SERVER_USER }}
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          script: |
            cd /var/www/myapp
            git pull origin main
            npm ci --production
            pm2 restart myapp

The workflow runs tests on every push or pull request to main. If tests succeed and the push targets main, the deployment job logs into the server, pulls the latest code, installs production dependencies, and restarts the application with pm2.