bindfs  -  http://bindfs.org/

-- Overview --

bindfs is a FUSE filesystem for mirroring a directory to another
directory, similarly to mount --bind. The permissions of the mirrored
directory can be altered in various ways.

Some things bindfs can be used for:
 - Making a directory read-only.
 - Making all executables non-executable.
 - Sharing a directory with a list of users (or groups).
 - Modifying permission bits using rules with chmod-like syntax.
 - Changing the permissions with which files are created.

Non-root users can use almost all features, but most interesting
use-cases need user_allow_other to be defined in /etc/fuse.conf


-- Installation --

Make sure fuse 2.6.0 or above is installed (http://fuse.sf.net/).
Then compile and install as usual:
./configure
make
make install

If you want the mounts made by non-root users to be visible to other users,
you may have to add the line user_allow_other to /etc/fuse.conf.


-- Usage --

See the bindfs --help or the man-page for instructions and examples.

-- OS X note --

The following extra options may be useful under osxfuse:
-o local,allow_other,extended_security,noappledouble

See https://github.com/osxfuse/osxfuse/wiki/Mount-options for details.

-- License --

GNU General Public License version 2 or any later version.
See the file COPYING.