Could I change my name and surname in all previous commits?

Question

Use git-filter-branch.

git filter-branch --commit-filter 'if [ "$GIT_AUTHOR_NAME" = "Josh Lee" ];
  then export GIT_AUTHOR_NAME="Hobo Bob"; export [email protected];
  fi; git commit-tree "$@"'

This only affects the author, not the committer (which for most commits will be the same as the author). If you want to rewrite those as well, set the GIT_COMMITTER_NAME and GIT_COMMITTER_EMAIL variables.

The standard warning about rewriting history applies; only do it to history that has not yet been shared.

June 2018 Update

The manual now includes a solution, using --env-filter, in its examples: https://git-scm.com/docs/git-filter-branch#_examples :

git filter-branch --env-filter '
    if test "$GIT_AUTHOR_EMAIL" = "root@localhost"
    then
        [email protected]
    fi
    if test "$GIT_COMMITTER_EMAIL" = "root@localhost"
    then
        [email protected]
    fi
' -- --all

To rewrite both author and commiter in all selected commits:

git filter-branch --commit-filter \
'if [ "$GIT_AUTHOR_NAME" = "OldAuthor Name" ]; then \
export GIT_AUTHOR_NAME="Author Name";\
export [email protected];\
export GIT_COMMITTER_NAME="Commmiter Name";\
export [email protected];\
fi;\
git commit-tree "$@"'

If there are no other authors, you can do:

git filter-branch --commit-filter 'export GIT_AUTHOR_NAME="authorname"; \
export [email protected]; git commit-tree "$@"'

Save the script below as e.g. ~/.bin/git-replace-author and run it using, e.g:

git replace-author "John Ssmith" "John Smith" "[email protected]"

With no arguments, it updates all commits with your name to use your current email address according to Git config.

DEFAULT_NAME="$(git config user.name)"
DEFAULT_EMAIL="$(git config user.email)"
export OLD_NAME="${1:-$DEFAULT_NAME}"
export NEW_NAME="${2:-$DEFAULT_NAME}"
export NEW_EMAIL="${3:-$DEFAULT_EMAIL}"

echo "Old:" $OLD_NAME "<*>"
echo "New:" "$NEW_NAME <$NEW_EMAIL>"
echo "To undo, use: git reset $(git rev-parse HEAD)"

git filter-branch --env-filter \
'if [ "$GIT_AUTHOR_NAME" = "${OLD_NAME}" ]; then
    export GIT_AUTHOR_NAME="${NEW_NAME}"
    export GIT_AUTHOR_EMAIL="${NEW_EMAIL}"
    export GIT_COMMITTER_NAME="${NEW_NAME}"
    export GIT_COMMITTER_EMAIL="${NEW_EMAIL}"
fi'

Raw (to download)

Only if you haven't pushed your commits to the world. Other wise everyone else has your old name in their repo which is unlikely you can change everyone's.

With Git 2.24 (Q4 2019), git filter-branch (and BFG) is deprecated.

The equivalent would be, using newren/git-filter-repo, and its example section:

cd repo
git filter-repo --mailmap my-mailmap

with my-mailmap:

Correct Name <[email protected]> <[email protected]>

That would replace the author name and email of any commit done by anyone with <[email protected]>

See git shortlog mapping author section for the exact syntax of