Git Commit Author Identity

Git commit author identity across repos

When to use

You're about to create a commit in a repo whose default identity may not match the user's intent — a freshly cloned sibling repo, a throwaway scratch clone, or a CI-like environment where user.name / user.email are unset. Common trigger: the user says "use the same identity as ".

Problem

Two recurring failures:

1. Committing with the wrong identity (e.g. a work email into a personal OSS repo, or root@hostname from an unconfigured clone).

2. Trying to override per-command with git -c user.name='First Last' and having the shell split the quoted value, so git sees user.name=First and treats Last as the next config key:

   error: key does not contain a section: useAdd
   fatal: unable to parse command-line config
   

   Or, if it parses, the committed author ends up as First_Last / First because quoting was stripped somewhere along the pipeline.

Solution

1. Read the target identity from an existing repo the user trusts:

   git -C /path/to/reference-repo config user.name
   git -C /path/to/reference-repo config user.email
   

2. Commit using environment variables, which survive any shell quoting shenanigans:

   GIT_AUTHOR_NAME="First Last" \
   GIT_AUTHOR_EMAIL="me@example.com" \
   GIT_COMMITTER_NAME="First Last" \
   GIT_COMMITTER_EMAIL="me@example.com" \
   git -C /path/to/repo commit -F .commit_msg.tmp
   

3. Verify immediately before pushing:

   git -C /path/to/repo log -n1 --format='author=%an <%ae>%n committer=%cn <%ce>'
   

4. If you got it wrong, fix in place with --amend --reset-author (only safe if you haven't pushed yet):

   GIT_AUTHOR_NAME="First Last" GIT_AUTHOR_EMAIL="me@example.com" \
   GIT_COMMITTER_NAME="First Last" GIT_COMMITTER_EMAIL="me@example.com" \
   git -C /path/to/repo commit --amend --no-edit --reset-author
   

Example

Wrong (will sometimes give First_Last as the author, sometimes error out with key does not contain a section):

git -c user.name='First Last' -c user.email=me@example.com commit -m "msg"

Right:

GIT_AUTHOR_NAME="First Last" GIT_AUTHOR_EMAIL="me@example.com" \
GIT_COMMITTER_NAME="First Last" GIT_COMMITTER_EMAIL="me@example.com" \
git commit -F .commit_msg.tmp

Pitfalls

• git -c does work on the shell in a normal terminal, but through agent tools the quoting is lossy. Env vars are the safe default.
• --reset-author only rewrites the author by default; set both GIT_AUTHOR_* and GIT_COMMITTER_* or the committer will keep the old identity.
• Once pushed, rewriting author requires a force-push; prefer to get it right on the first commit.

See also

• shell-heredoc-and-multiline-strings
• github-pr-via-gh-cli