[PATCH] git-filter-branch: Add an example on how to remove empty commits

[Petr Baudis <pasky@suse.cz>]

From: Sverre Rabbelier <srabbelier@gmail.com>

Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Petr Baudis <pasky@suse.cz>
---
 Documentation/git-filter-branch.txt |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index fed6de6..2565244 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -246,6 +246,21 @@ git filter-branch --commit-filter '
 	fi' HEAD
 ------------------------------------------------------------------------------
 
+To remove commits that are empty (do not introduce any change):
+
+------------------------------------------------------------------------------
+git rev-list HEAD | while read c; do [ -n "$(git diff-tree --root $c)" ] || echo $c; done > revs
+
+git filter-branch --commit-filter '
+  if grep -q "$GIT_COMMIT" '"$(pwd)/"revs';
+  then
+    skip_commit "$@";
+  else
+    git commit-tree "$@";
+  fi' HEAD
+
+------------------------------------------------------------------------------
+
 The function 'skip_commit' is defined as follows:
 
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-- 
1.5.6.3.536.g61aad