git add and commit: Messages Worth Reading

git add stages; git commit records. Everything else in git — branches, merges, rebases — moves commits around, but this pair is where every change enters history, and the craft is in what you stage and what you write.

Staging with intent #

$ git add src/blog.js          # one file
$ git add -p                    # choose hunks interactively
$ git add -A                    # everything, including new files

-p is the honesty feature: it walks each hunk, and y/n/s (split) let you stage a logical change out of a messy working tree. Two unrelated fixes in one file? Stage them as two commits — status shows the split the whole way.

Committing #

$ git commit -m "fix: correct cache headers on media responses"
$ git commit                    # opens the editor for the long form

The long form is worth the habit for anything non-trivial:

fix: correct cache headers on media responses

The media route set max-age=0 after the immutable change,
so browsers revalidated every asset. Restore the one-year
header and keep nosniff.

Subject in the imperative ("fix", not "fixed"), under 50 characters, blank line, then the why — the what is visible in the diff.

Amending and empty commits #

$ git add forgotten.js
$ git commit --amend --no-edit
$ git commit --amend -m "fix: correct cache headers on media"   # new message

Amend rewrites the last commit — perfect before it is pushed, forbidden after. The empty commit (--allow-empty) marks events in history: a deploy, a release gate.

The craft rules #

The granularity rule pays off downstream: cherry-pick moves exactly one logical change, revert undoes exactly one, and reviewers read one idea at a time.

History rewriting for clean lines is rebase; combining commits is its interactive form. The Git series continues.