tree=$1
shift
-ver=$1
-shift
+if [ "$1" ]; then
+ ver="next-${1#next-}"
+ shift
+else
+ ver=$(git tag -l next-\* | sort | tail -n 1)
+fi
-rev=$(git show next-${ver}:Next/SHA1s | sed -n "s/^$tree\t\t*//p")
+rev=$(git show ${ver}:Next/SHA1s | sed -n "s/^$tree\t\t*//p")
[ "$rev" ] || {
echo "No such tree/date" 1>&2
exit 1