Written to change the unix name used for a cvs commit to a pretty git name for the user. Implementation borrowed from http://lists.freedesktop.org/archives/portland/2010-October.txt author-conv-file format (same format as git-cvsimport requires):

git_fix_author

#!/bin/bash

export $authors_file=author-conv-file

git filter-branch -f --env-filter '

get_name () {
    grep "^$1=" "$authors_file" |
        sed "s/^.*=\(.*\) <.*>$/\1/"
}

get_email () {
    grep "^$1=" "$authors_file" |
        sed "s/^.*=.* <\(.*\)>$/\1/"
}

GIT_AUTHOR_NAME=$(get_name $GIT_COMMITTER_NAME) &&
GIT_AUTHOR_EMAIL=$(get_email $GIT_COMMITTER_NAME) &&
GIT_COMMITTER_NAME=$GIT_AUTHOR_NAME &&
GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL &&
export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL &&
export GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL
' -- --all

Sample author-conv-file:

john=John Doe <john.doe@hotmail.com>
jill=Jill Doe <jill.doe@hotmail.com>