Renaming your username in Git commits

This script will do the trick:

git filter-branch -f --commit-filter '
    if [ "$GIT_AUTHOR_NAME" = "Dead Name" -o "$GIT_COMMITTER_NAME" = "Dead Name" ];
    then
        GIT_AUTHOR_NAME="Actual Name";
        GIT_COMMITTER_NAME="Actual Name";
        git commit-tree "$@";
    else
        git commit-tree "$@";
    fi' HEAD

Caveats:

• It will strip GPG signatures, even if the commit (including its parent) doesn’t change. Ugh.
• Obviously rewrites history, and needs quite a massive force-push (so probably not good for multi-person projects. *tears*)
• It assumes AUTHOR_NAME == COMMITTER_NAME (if you’re in only one of the two, this will (probably-incorrectly) take ownership of both fields)
• It’s a crappy script and can be improved a lot.

Notes:

• Git commits have TWO names: the author, and the committer. There’s a logical reason behind this, but google is going to be way better at explaining why than me. Just keep in mind to change both the committer and the author, assuming they’re the same.

Source: https://stackoverflow.com/a/2931914