diff --git a/dobackup b/dobackup
index f479f02..40ae764 100755
--- a/dobackup
+++ b/dobackup
@@ -19,6 +19,12 @@
 ##################################################################
 
 
+if [ -z $1 ]; then
+    echo "usage: dobackup FILE"
+    echo "need file with backup instructions"
+    exit 1
+fi
+
 name=`basename $1`
 source $1