AI Agent Engineer

AI Agent Engineer

Git Cheat Sheet: Commits and Pre-Commit Checks

3 min read

Commits and Pre-Commit Checks

A commit writes the directory tree selected by the staging area as a new snapshot and records its parent, author, time, and message. It is not “saving the whole working tree.” See Git State Model and Commit Graph for the full structure. A good commit has clear scope, a readable message, and no unrelated files.

git commit

git commit

Purpose: create a commit and open the default editor for its message.

Appropriate when:

  • the explanation is long enough to need a subject and body;
  • a team expects a message to explain context, risk, or verification.

Suggested messages:

  • Put a short subject on the first line, such as fix: handle empty config path.
  • If needed, add a blank line, then explain reason, impact, and verification.

git commit -m "message"

git commit -m "message"

Purpose: create a commit with an inline command-line message.

Appropriate when:

  • the change is small or its explanation short;
  • an automation script or quick local snapshot needs a message.

Example:

git commit -m "docs: add git cheat sheet notes"

Notes:

  • In Windows PowerShell, both single and double quotes express strings, but a double-quoted message interpolates PowerShell variables or escape sequences.
  • Still inspect git diff --staged before committing; do not rely only on the commit message.

git commit -am "message"

git commit -am "message"

Purpose: stage modifications to all tracked files, then commit.

Appropriate when:

  • every modification is to an already tracked file;
  • no new file is involved.

Limits:

  • It does not automatically include untracked new files.
  • It can combine unrelated modifications across tracked files. Before running it, inspect:
git status --short
git diff

Pre-commit check flow

A recommended minimum flow:

git status --short
git diff
git add -- README.md
git diff --staged
git commit -m "type: short message"
  • git status --short quickly confirms the change list.
  • git diff shows unstaged content.
  • git diff --staged shows what will enter the commit.
  • If the project provides tests, lint, or formatting commands, run the relevant validation before committing.

Correct a message or add a missed file

If you immediately find a wrong message or missed staging a file, use:

git commit --amend

See History Rewriting and Failure Recovery for details. If others already use the commit, be cautious before altering history.

Completion check

  • Every line in git diff --staged belongs to one clear intent.
  • git status --short has no unexpected credentials, caches, lock files, or large files.
  • After committing, git show --stat --oneline HEAD explains what the snapshot did.
  • Required project tests, lint, or document checks actually ran and their results were recorded honestly.

Backlinks