put in ${HOME}/bin/git_fix and `chmod +x` it after you install

git_fix

#!/bin/sh
USAGE="Command Usage:\n\ngit_fix 'email, name' 'old value' 'new value'\n";
if [ "$#" -ne 3 ]; then
    echo ${USAGE}
else
    case "$1" in
        'email')
            echo "Changing email from: '$2' to '$3'"
            git filter-branch --env-filter "
            if [ \"\$GIT_COMMITTER_EMAIL\" = \"$2\" ]
            then
                export GIT_COMMITTER_EMAIL=\"$3\"
            fi
            if [ \"\$GIT_AUTHOR_EMAIL\" = \"$2\" ]
            then
                export GIT_AUTHOR_EMAIL=\"$3\"
            fi
            " --force --tag-name-filter cat -- --branches --tags
        ;;
        'name')
            echo "Changing name from: '$2' to '$3'"
            git filter-branch --env-filter "
            if [ \"\$GIT_COMMITTER_NAME\" = \"$2\" ]
            then
                export GIT_COMMITTER_NAME=\"$3\"
            fi
            if [ \"\$GIT_AUTHOR_NAME\" = \"$2\" ]
            then
                export GIT_AUTHOR_NAME=\"$3\"
            fi
            " --force --tag-name-filter cat -- --branches --tags
        ;;
        *)
            echo ${USAGE}
        ;;
    esac
fi