Changing commit author and dates

Every commit carries two identities: the author and the committer, each with its own date. The author is who originally wrote the change; the committer is who last applied it. Normally they are the same person, but they diverge when someone applies a patch you wrote, or when a rebase replays your commits (you stay author, the rebaser becomes committer). See both:

git show --format=fuller HEAD
# Author:     Jane Dev <jane@old.local>   AuthorDate: ...
# Commit:     Jane Dev <jane@work.com>    CommitDate: ...

This distinction matters because most commands change only the author unless you also act on the committer — and git log shows the author by default, so author is usually what you actually want to fix.

Fix the last commit’s author with --amend --author, or adopt your current identity with --reset-author. Two everyday fixes for the most recent commit:

# Set a specific author explicitly:
git commit --amend --author="New Name <new@email.com>" --no-edit

# Or stamp it with whatever your current git config identity is:
git commit --amend --reset-author --no-edit

--author= overrides just the author field; --reset-author sets both author and committer to your current user.name / user.email (and resets the author date to now). --no-edit keeps the existing message. Both rewrite the last commit into a new SHA, exactly like any other amend.

Set commit dates with the GIT_AUTHOR_DATE / GIT_COMMITTER_DATE environment variables, or --date for the author date alone. Dates are just metadata fields, and you can set them explicitly:

# --date affects only the AUTHOR date:
git commit --amend --date="2026-05-01T09:00:00" --no-edit

# Set BOTH author and committer dates by exporting env vars:
GIT_AUTHOR_DATE="2026-05-01T09:00:00" \
GIT_COMMITTER_DATE="2026-05-01T09:00:00" \
git commit --amend --no-edit

The trap: --date moves only the author date, leaving the committer date untouched, so the two can silently disagree. When you need both aligned, set both env vars. Git accepts ISO-8601, RFC 2822, and relative forms like "2 days ago".

Change author across MANY commits with an interactive rebase or a rebase --exec range. For several commits, two approaches. Mark each target edit in an interactive rebase and amend at every stop:

git rebase -i <base>        # mark the commits to fix as 'edit'
# at each stop:
git commit --amend --author="New Name <new@email.com>" --no-edit
git rebase --continue

Or run a command automatically across a whole range — here, resetting every commit’s author to your current identity:

git rebase -r <base> --exec 'git commit --amend --reset-author --no-edit'

--exec runs the given command after replaying each commit in the range, so you fix dozens of commits without stopping at each one.

For a wrong email on the entire history, use git filter-repo — and prefer a .mailmap when you only need correct display. To rewrite authorship across all commits (e.g. a leaked or wrong email on every one), the modern tool is git filter-repo:

# mailmap.txt maps old identities to new ones, then rewrites every commit:
git filter-repo --mail-map mailmap.txt

git filter-branch did this historically but is deprecated — it is slow and full of footguns; filter-repo is the officially recommended replacement. But if you only need names/emails to appear correct in git log and git shortlog without touching history at all, add a .mailmap file at the repo root:

Correct Name <correct@email.com> <old@wrong.com>

A .mailmap remaps identities at display time only — no SHAs change, no force-push, no coordination. Reach for it first whenever display correctness is all you actually need.