git-author-rewrite

#!/bin/bash
#|
#| Rewrites author/committer name/e-mail in commit history.
#|
#| Usage:
#|
#| git-author-rewrite OPTIONS [-- ARGUMENTS]
#|
#| Options:
#|   -c, --committer      rewrite committer
#|   -e, --email EMAIL    sets the e-mail to replace
#|   -f, --force          force backup overwrite
#|   -n, --name NAME      sets the name to replace
#|   -h, --help           show this help and exit
#|   -ne, --new-email     the new e-mail
#|   -nn, --new-name      the new name
#|
#| Notes:
#|   - At least one name/e-mail and the its update must be provided.
#|   - Anything beyond '--' argument is passed as arguments to the 'git filter'
#      command.
#|   - For all matches, both author/committer name and e-mail will be replaced
#|     (if both are provided).
#|   - To push the changes use the following command:
#|
#|     git push --force --tags origin 'refs/heads/*'"
#|
#|     The easiest way to use is applying this command on a bare repository and
#|     then force-push it back to its origin.
#|

# Based on following sources:
#
# https://gist.github.com/octocat/0831f3fbd83ac4d46451
# https://gist.github.com/frz-dev/adf8c2c7275da1369e0cc340feda0ba0
# https://gist.github.com/octocat/0831f3fbd83ac4d46451#gistcomment-2178506

EX_ERROR=1

SCRIPT_FILE="${BASH_SOURCE[0]}"
while [[ $# -gt 0 ]]; do
    case "$1" in
    -c|--committer)
        COMMITTER="true"
      	shift
        ;;

    -e|--email)
      	CURRENT_EMAIL="$2"
      	shift 2
        ;;

    -n|--name)
      	CURRENT_NAME="$2"
      	shift 2
        ;;

    -h|--help)
        sed '/#|.*/ s/^#|[[:space:]]\?//p;d' < "$SCRIPT_FILE"
        exit $EX_ERROR
        ;;

    -ne|--new-email)
      	NEW_EMAIL="$2"
      	shift 2
        ;;

    -nn|--new-name)
      	NEW_NAME="$2"
      	shift 2
        ;;

    --)
        shift
        break
        ;;

    -*)
        echo "Unknown option encountered: '$1'" >&2
        exit $EX_ERROR
        ;;

    *)
        break
        ;;
    esac
done

if [[ -z "$CURRENT_EMAIL" && -z "$CURRENT_NAME" ]]; then
   echo "Specify name or e-mail." >&2
   exit EX_ERROR
fi

if [[ -z "$NEW_EMAIL" && -z "$NEW_NAME" ]]; then
   echo "Specify new name or new e-mail." >&2
   exit EX_ERROR
fi

git filter-branch --env-filter "
   if [ \"\$GIT_AUTHOR_NAME\" = \"${CURRENT_NAME}\" ] || [ \"\$GIT_AUTHOR_EMAIL\" = \"${CURRENT_EMAIL}\" ]
   then
      [ ! -z \"$NEW_NAME\" ] && export GIT_AUTHOR_NAME=\"${NEW_NAME}\"
      [ ! -z \"$NEW_EMAIL\" ] && export GIT_AUTHOR_EMAIL=\"${NEW_EMAIL}\"
   fi

   if ( [ \"\$GIT_COMMITTER_EMAIL\" = \"${CURRENT_EMAIL}\" ] ) && [ \"$COMMITTER\" = \"true\" ] && [ ! -z \"$NEW_EMAIL\" ]
   then
      export GIT_COMMITTER_EMAIL=\"${NEW_EMAIL}\"
   fi

   if [ \"\$GIT_COMMITTER_NAME\" = \"${CURRENT_NAME}\" ] && [ \"$COMMITTER\" = \"true\" ] && [ ! -z \"$NEW_NAME\" ]
   then
      export GIT_COMMITTER_NAME=\"${NEW_NAME}\"
   fi
   " $@ --tag-name-filter cat -- --branches --tags