git add 指令
當執行了 add 指令，檔案放到預備「物件儲存」中，具有物件獨特的 sha 碼，Git 替這些更動建立了索引 (index)，隨時可以被 commit 進儲存庫中。
常用範例
| 範例 | 說明 |
|---|---|
| git add README.txt | 將指定的檔案建立 index |
| git add . | 將目前目錄現在更變建立 index |
| git add --all | 將所有變動的檔案建立 index |
🤔 `git add .` 跟 `git add --all` 有什麼不同？
語法結構
usage: git add [<options>] [--] <pathspec>...
-n, --dry-run dry run
-v, --verbose be verbose
-i, --interactive interactive picking
-p, --patch select hunks interactively
-e, --edit edit current diff and apply
-f, --force allow adding otherwise ignored files
-u, --update update tracked files
-N, --intent-to-add record only the fact that the path will be added later
-A, --all add changes from all tracked and untracked files
--ignore-removal ignore paths removed in the working tree (same as --no-all)
--refresh don't add, only refresh the index
--ignore-errors just skip files which cannot be added because of errors
--ignore-missing check if - even missing - files are ignored in dry run