diff --git a/git/README b/git/README
index 8fbf75f..46cf251 100644
--- a/git/README
+++ b/git/README
@@ -28,3 +28,21 @@ in a directory in the PATH (for instance /usr/local/bin) and add an
 alias:
 
  git config --global alias.cherry-move "\!sh -c 'git-cherry-move'"
+
+
+# git-merge-ff-only #
+
+git-merge-ff-only main_branch topic_branch is the equivalent of the
+following commands:
+
+ git checkout main_branch && git merge --ff-only topic_branch
+
+except that main_branch is not checked out. The reference is updated
+directly (if possible), and HEAD stays on whatever branch was checked
+out before running the command.
+
+To activate the git merge-ff-only command, put the git-merge-ff-only
+script in a directory in the PATH (for instance /usr/local/bin) and
+add an alias:
+
+ git config --global alias.merge-ff-only "\!sh -c 'git-merge-ff-only'"
diff --git a/git/git-merge-ff-only b/git/git-merge-ff-only
new file mode 100755
index 0000000..55fe8da
--- /dev/null
+++ b/git/git-merge-ff-only
@@ -0,0 +1,38 @@
+#!/bin/sh
+#
+# git-merge-ff-only, Copyright © 2012 Matteo Cypriani
+#
+# This program is free software. It comes without any warranty, to
+# the extent permitted by applicable law. You can redistribute it
+# and/or modify it under the terms of the Do What The Fuck You Want
+# To Public License, Version 2, as published by Sam Hocevar. See
+# http://sam.zoy.org/wtfpl/COPYING for more details.
+#
+# This script fast-forwards a branch (main_branch) to another branch
+# (topic_branch), if possible. It is equivalent to git checkout
+# main_branch && git merge --ff-only topic_branch, but the effort of
+# checking out the main branch is saved (git branch -f is used to update
+# the reference directly).
+
+set -e
+
+if [ $# -ne 2 ] ; then
+	echo "Usage: $0 <main_branch> <topic_branch>"
+	echo "<main_branch> will be fast-forwarded to <topic_branch> if possible."
+	exit 1
+fi
+
+MAIN_BRANCH="$1"
+TOPIC_BRANCH="$2"
+
+echo "Trying to merge $TOPIC_BRANCH into $MAIN_BRANCH..."
+
+DIFF="$(git rev-list "$TOPIC_BRANCH".."$MAIN_BRANCH")"
+if [ -z "$DIFF" ] ; then
+	echo "$TOPIC_BRANCH contains all the commits of $MAIN_BRANCH."
+	echo "Fast-forwarding $MAIN_BRANCH to $TOPIC_BRANCH."
+	git branch -f "$MAIN_BRANCH" "$TOPIC_BRANCH"
+else
+	echo "$TOPIC_BRANCH does not contain all the commits of $MAIN_BRANCH."
+	echo "Fast-forward impossible, aborting."
+fi