diff --git a/namen.sh b/namen.sh
index 51351d1..36f989b 100755
--- a/namen.sh
+++ b/namen.sh
@@ -6,7 +6,7 @@ usage() {
 gebruik:
 
     $PROGNAME [opties] -i
-    $PROGNAME [opties] file.data.dz ...
+    $PROGNAME [opties] corpusfile(s) en/of corpusdirectory(s)
 
     -i     : kies interactief
 
@@ -72,10 +72,13 @@ search () {
 for i in "$@"
 do
     case "$i" in
-        *.data.dz)
+        *.xml|*.dact|*.dbxml|*.data.dz|*.index|*.zip)
             ;;
         *)
-            usage
+            if [ ! -d "$i" ]
+            then
+                usage
+            fi
             ;;
     esac
 done