diff --git a/install.sh b/install.sh
index 885f71b..0559ac4 100755
--- a/install.sh
+++ b/install.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 set -e
 
@@ -20,6 +20,6 @@ EOF
 chmod +x $DESTDIR$PREFIX/bin/zjunet
 echo "[INFO] Done."
 echo
-if [[ -z $DESTDIR ]]; then
-	zjunet usage
+if [ -z $DESTDIR ]; then
+	 $DESTDIR$PREFIX/bin/zjunet usage
 fi
diff --git a/uninstall.sh b/uninstall.sh
index 3562a8b..c738b08 100755
--- a/uninstall.sh
+++ b/uninstall.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 PREFIX=/usr/local