don't allow empty format string
authorceriel <none@none>
Thu, 15 Nov 1990 17:00:39 +0000 (17:00 +0000)
committerceriel <none@none>
Thu, 15 Nov 1990 17:00:39 +0000 (17:00 +0000)
commit715dd4ef0f4941040478d9eac3412994769e89ac
tree77f5b2f4280664d29b52a05418876a2ca5841ed6
parenta06482bb415068c2d9161e95182230d774a31c21
don't allow empty format string
util/grind/commands.g