Are you sure that awk is installed on every system? I think, using grep is the better solution as grep is always installed.

I know no system where awk is not installed. Do you? Grep is not the same result. With awk each device is only listed once even if the bind mount points are not in /var/www

I`m running debian and opensuse on on both systems awk is installed by default. Maybe this is the same on other os. Never checked it out. ;)

Removing all mount-binds is a good idea.