From 030dde227a9b2f5e9cf029c43db3741cf70222ce Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Sun, 20 Jan 2013 20:01:59 -0800
Subject: [PATCH] promptive error message

---
 weed-fs/src/cmd/weed/export.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/weed-fs/src/cmd/weed/export.go b/weed-fs/src/cmd/weed/export.go
index ae9f5f212..27c353b28 100644
--- a/weed-fs/src/cmd/weed/export.go
+++ b/weed-fs/src/cmd/weed/export.go
@@ -40,6 +40,10 @@ func runExport(cmd *Command, args []string) bool {
 		return false
 	}
 
+  if *dest!="" && !strings.HasSuffix(*dest, ".tar") {
+    fmt.Println("the output file", *dest, "should ends with .tar")
+    return false
+  }
 	var err error
 	if strings.HasSuffix(*dest, ".tar") {
 		var fh *os.File