. git-sh-setup || die "Not a git archive"
+usage () {
+ echo >&2 "usage: $(basename $0)"' [<branchname> [start-point]]
+
+If no arguments, show available branches and mark current branch with a star.
+If one argument, create a new branch <branchname> based off of current HEAD.
+If two arguments, create a new branch <branchname> based off of <start-point>.
+'
+ exit 1
+}
+
case "$#" in
0)
headref=$(readlink "$GIT_DIR/HEAD" | sed -e 's|^refs/heads/||')
head="$2^0" ;;
esac
branchname="$1"
+
+case "$branchname" in
+-*)
+ usage;;
+esac
+
rev=$(git-rev-parse --verify "$head") || exit
[ -e "$GIT_DIR/refs/heads/$branchname" ] && die "$branchname already exists"