git-empty-branch

#!/bin/sh
#
#    Copyright 2010 Joel Weinberger
#
#    This program is free software: you can redistribute it and/or modify it
#    under the terms of the GNU General Public License as published by the Free
#    Software Foundation, either version 3 of the License, or (at your option)
#    any later version.
#
#    This program is distributed in the hope that it will be useful, but WITHOUT
#    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
#    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
#    more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This script creates a branch in a git repository with an empty history. This
# puts the new branch in effectively the same state as the first branch when you
# create a new, empty repository. Of course, it leaves all of your other
# branches the same and untouched.
#
set -e

USAGE="git-emtpy-branch <new-branch>"

if [ $# != 1 ]; then
	echo "usage: $USAGE" >&2
	exit 1
fi

# Thanks to 'set -e' above, this will exit with a useful error message if we are
# not in a git repository. Thus, there is no reason to check its output. Another
# 'set -e' win!
GITTOPLEVEL=`git rev-parse --show-toplevel`
cd $GITTOPLEVEL

git symbolic-ref HEAD refs/heads/$1
rm .git/index
git clean -fdxq

echo "You probably want to change directories to the top level now:"
echo $GITTOPLEVEL