Spliting commits, and filter-branch

http://progit.org/book/ch6-4.html
Splitting a Commit

git rebase -i HEAD~3
(change the commit to edit)

(now we are at the commit, commited, which we want to change)
git reset HEAD^

(change, commit, whatever is needed)

git add -p
git ci
git add -p
git ci
(...)

git rebase --continue

The Nuclear Option: filter-branch
Removing a File from Every Commit (slower)

git filter-branch --tree-filter 'rm -f passwords.txt' HEAD

Removing a File/Directory from Every Commit (faster)

git filter-branch --index-filter 'git rm --cached --ignore-unmatch filename' HEAD

Making a Subdirectory the New Root

git filter-branch --subdirectory-filter trunk HEAD

Changing E-Mail Addresses Globally

git filter-branch --commit-filter '
        if [ "$GIT_AUTHOR_EMAIL" = "schacon@localhost" ];
        then
                GIT_AUTHOR_NAME="Scott Chacon";
                GIT_AUTHOR_EMAIL="schacon@example.com";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD

All commit (HEAD), or last part of commit XXXXX..HEAD is valid.

---

git-filter-branch(1): Rewrite branches - Linux man page
http://linux.die.net/man/1/git-filter-branch

Extracting a subdirectory from git as a new git repository
http://www.pither.com/articles/2009/02/04/extracting-a-subdirectory-from-git-as-a-new-git-repository

Checkout subdirectories in Git?
http://stackoverflow.com/questions/180052/checkout-subdirectories-in-git

Splitting a subpath out into a new repo
http://help.github.com/splitting-a-subpath-to-a-new-repo/