How to change the language of pages in OpenCms

I wanted to change the language of pages in the controlcode. There is a something in the "Content Tools" of OpenCms called "Change Element Locale", but that only change the locale-property on pages. So I exported the content (Export Database) unzipped it, used the following basch command line:

find .-name *.html -type f -print0 | xargs -0 sed -i 's/language="de"/language="en"/g'

then I zipped it up again and imported the zip to OpenCms.