by the following (quick and very dirty) perl regexp : perl -0777pi.bak -e 'print m!CGAL_USE_QT(.|[\r\n])*CGAL/basic!g;' */demo/*/*.C
by the following (quick and very dirty) perl regexp : perl -0777pi.bak -e 'print m!CGAL_USE_QT(.|[\r\n])*CGAL/basic!g;' */demo/*/*.C