convenience functions, too. For example, calling 'skip_commit "$@"'
will leave out the current commit (but not its changes! If you want
that, use 'git-rebase' instead).
++
+You can also use the 'git_commit_non_empty_tree "$@"' instead of
+'git commit-tree "$@"' if you don't wish to keep commits with a single parent
+and that makes no change to the tree.
--tag-name-filter <command>::
This is the filter for rewriting tag names. When passed,
The result will contain that directory (and only that) as its
project root.
+--prune-empty::
+ Some kind of filters will generate empty commits, that left the tree
+ untouched. This switch allow git-filter-branch to ignore such
+ commits. Though, this switch only applies for commits that have one
+ and only one parent, it will hence keep merges points. Also, this
+ option is not compatible with the use of '--commit-filter'. Though you
+ just need to use the function 'git_commit_non_empty_tree "$@"' instead
+ of the 'git commit-tree "$@"' idiom in your commit filter to make that
+ happen.
+
--original <namespace>::
Use this option to set the namespace where the original commits
will be stored. The default value is 'refs/original'.
Now, you will get the rewritten history saved in HEAD.
+As with using `rm filename`, `git rm --cached filename` will fail
+if the file is absent from the tree of a commit. If it is not important
+whether the file is already absent from the tree, you can use
+`git rm --cached --ignore-unmatch filename` instead.
+
To rewrite the repository to look as if `foodir/` had been its project
root, and discard all other history:
---------------------------------------------------------------
+
+Checklist for Shrinking a Repository
+------------------------------------
+
+git-filter-branch is often used to get rid of a subset of files,
+usually with some combination of `\--index-filter` and
+`\--subdirectory-filter`. People expect the resulting repository to
+be smaller than the original, but you need a few more steps to
+actually make it smaller, because git tries hard not to lose your
+objects until you tell it to. First make sure that:
+
+* You really removed all variants of a filename, if a blob was moved
+ over its lifetime. `git log \--name-only \--follow \--all \--
+ filename` can help you find renames.
+
+* You really filtered all refs: use `\--tag-name-filter cat \--
+ \--all` when calling git-filter-branch.
+
+Then there are two ways to get a smaller repository. A safer way is
+to clone, that keeps your original intact.
+
+* Clone it with `git clone +++file:///path/to/repo+++`. The clone
+ will not have the removed objects. See linkgit:git-clone[1]. (Note
+ that cloning with a plain path just hardlinks everything!)
+
+If you really don't want to clone it, for whatever reasons, check the
+following points instead (in this order). This is a very destructive
+approach, so *make a backup* or go back to cloning it. You have been
+warned.
+
+* Remove the original refs backed up by git-filter-branch: say `git
+ for-each-ref \--format="%(refname)" refs/original/ | xargs -n 1 git
+ update-ref -d`.
+
+* Expire all reflogs with `git reflog expire \--expire=now \--all`.
+
+* Garbage collect all unreferenced objects with `git gc \--prune=now`
+ (or if your git-gc is not new enough to support arguments to
+ `\--prune`, use `git repack -ad; git prune` instead).
+
+
Author
------
Written by Petr "Pasky" Baudis <pasky@suse.cz>,