Update INSTALL_OSX.md

INSTALL_OSX.md

@@ -7,8 +7,7 @@ You need Xcode or a C/C++ compilation (clang, g++, ..).
 
 Copy past this line in a terminal
 
-    curl -sS https://git.u-cergy.fr/blaar/blaar/raw/master/developer_tools/clone_and_install_blaar_osx.sh | bash &&
-    cd blaar
+    curl -sS https://git.u-cergy.fr/blaar/blaar/raw/master/developer_tools/clone_and_install_blaar_osx.sh | bash
 
 You can do [**step by step**](https://git.u-cergy.fr/blaar/blaar/blob/master/developer_tools/clone_and_install_blaar_osx.sh) copying command line by command line. This may be useful to better understand and in case where the installer crash.