Subject: [PATCH] git-filter-branch: add --egrep-filter option

From: Michael O'Cleirigh <[email-masked]>
Date: Fri, 15 Apr 2011 18:50:24 -0400

The --subdirectory-filter will look for a single directory and then rewrite
history to make its content the root.  This is ok except for cases where we
want to retain history of those files before they were moved into that
directory.

The --egrep-filter option allows specifying an egrep regex for the files in the
tree of each commit to keep.  For example:

Directories we want are A, B, C, D and they exist in several different
lifetimes.  A and B exist sometimes together then B and C and finally then D.

e.g. git-filter-branch --egrep-filter "(A|B|C|D)"

Each commit will then contain different combination's of A or B or C or D (up to A and B and C and D).
---
  git-filter-branch.sh |   12 ++++++++++++
  1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 962a93b..2392ad6 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -101,6 +101,7 @@ USAGE="[--env-filter<command>] [--tree-filter<command>]
              [--index-filter<command>] [--parent-filter<command>]
              [--msg-filter<command>] [--commit-filter<command>]
              [--tag-name-filter<command>] [--subdirectory-filter<directory>]
+			[--egrep-filter<filter>]
              [--original<namespace>] [-d<directory>] [-f | --force]
              [<rev-list options>...]"

@@ -122,6 +123,7 @@ filter_msg=cat
  filter_commit=
  filter_tag_name=
  filter_subdir=
+filter_egrep=
  orig_namespace=refs/original/
  force=
  prune_empty=
@@ -191,6 +193,10 @@ do
  		filter_subdir="$OPTARG"
  		remap_to_ancestor=t
  		;;
+	--egrep-filter)
+		filter_egrep="$OPTARG"
+		remap_to_ancestor=t
+		;;
  	--original)
  		orig_namespace=$(expr "$OPTARG/" : '\(.*[^/]\)/*$')/
  		;;
@@ -317,6 +323,12 @@ while read commit parents; do
  		}
  	esac || die "Could not initialize the index"

+	if [ "$filter_egrep" ]; then
+
+		git ls-tree $commit | egrep "$filter_egrep" | git mktree | xargs git read-tree -i -m
+
+	fi
+
  	GIT_COMMIT=$commit
  	export GIT_COMMIT
  	git cat-file commit "$commit">../commit ||
-- 1.7.2.3