git add

# 1) The three areas
#   working tree   ── your files on disk
#   staging area  ── what will be in the next commit (also called 'the index')
#   repository     ── committed history
#
# git add moves working tree -> staging.

# 2) Status — see what's where
git status
# Shows:
#   Untracked    — new files, never staged
#   Modified     — changes in working tree, not staged
#   Staged       — added; ready for the next commit

# 3) Add a specific file
git add src/login.js

# Add a directory recursively
git add src/

# Add EVERYTHING — careful with this in big repos
git add .                          # everything from current dir down
git add -A                          # entire repo, including deletions outside cwd
git add -u                          # only update tracked files (no untracked)

# 4) Dry run — see what 'add .' would do without doing it
git add . --dry-run
git add -An .

# 5) Interactive add — pick files
git add -i
# Menu: status / update / revert / patch / diff / quit / help

# 6) Patch mode — stage SOME hunks of a file
git add -p src/login.js
# For each hunk, choose:
#   y — stage this hunk
#   n — skip
#   s — split into smaller hunks
#   e — edit hunk manually (advanced)
#   q — quit, keep what's already staged
# This is how you make focused, reviewable commits when you've made unrelated changes in one sitting.

# 7) Diff what you've staged
git diff             # working tree vs staging
git diff --staged    # staging vs last commit (a.k.a. --cached)
git diff HEAD        # working tree vs last commit (both modified and staged)

# 8) Unstage — move back from staging to working tree
git restore --staged src/login.js     # Git 2.23+
git reset HEAD src/login.js            # older form
# Working tree changes are kept; just the stage is reverted.

# 9) Discard working-tree changes (destructive — be sure)
git restore src/login.js                # working tree -> what's in staging or HEAD
git checkout -- src/login.js             # older form
# These DELETE uncommitted changes. There is no undo from here for those edits.

# 10) Add new files but not deletions (or the inverse)
git add --ignore-removal .             # adds new + modified, not deletions
git add -u                              # only tracked file updates (incl. deletions)

# 11) .gitignore — keep noise out of the staging area
# .gitignore (committed) vs .git/info/exclude (local only)
node_modules/
.env
.env.*
dist/
coverage/
*.log
.DS_Store
.idea/
.vscode/*
!.vscode/extensions.json    # negation — keep one specific file
# Already-tracked files are NOT ignored retroactively:
git rm --cached path/to/already-tracked

# 12) Force-add an ignored file (rare but useful for shared assets)
git add -f dist/critical.bundle.js

# 13) Verify before commit
git status -s              # short format
git diff --staged --stat   # file-level summary of staged changes

# 14) End-to-end
echo 'feature: add login' > NOTES.md
git status                  # NOTES.md is Untracked
git add NOTES.md            # now Staged
git diff --staged           # shows what will be committed
git commit -m 'docs: add login notes'
git log --oneline -n 1

# 15) Crafted-commit workflow (the real reason patch mode exists)
git status
# You see 3 unrelated changes in one file: a typo fix, a new feature, and a debug print.
git add -p src/login.js
#   stage the typo fix             → y
#   stage the new feature          → n (will be a separate commit)
#   stage the debug print          → n (don't even commit; restore later)
git commit -m 'fix: typo in login error message'
git add -p src/login.js
#   stage the new feature          → y
git commit -m 'feat: remember-me checkbox'
git restore src/login.js          # discard the debug print

# 16) Common bugs
#   • git add . on first commit → accidentally includes .env or node_modules → use .gitignore FIRST
#   • Editing a file after staging — the new edits are NOT in the upcoming commit
#       Fix: git add the file again, or git diff to confirm
#   • git reset HEAD~ — that's HISTORY rewrite, not unstage. Use git restore --staged instead.
#   • git checkout -- file inside a directory — discards uncommitted work; use git restore for clarity
#   • Force-adding .env — credentials in git history; once pushed, ROTATE them

git add file.txt
git add .            # everything in CWD
git add -p           # review hunks one by one