FUSE (Filesystem in Userspace) is an excellent way to hack up filesystems on various operating systems (it is supported best on Linux and BSD). The Fuse Perl module lets you write filesystems in Perl. Scary, but attractively easy!

I’ve written an extension, Fuse::Util, which provides fall-through methods that can be used to write a FUSE filing system which falls through to the underlying filesystem for some of its methods, and a few filesystems:

=loop_fs= A simple loopback filesystem. =metadata_fs= A loopback filesystem which presents the metadata of each file on the underlying filesystem as a file. A design for a more complex version which copes with directories as well is also given in the file @metadata_fs_ideal@. =filter_attr_fs= A filesystem which gives a filtered view of the underlying filesystem according to which objects possess a certain extended attribute. (This could easily be extended to arbitrary predicates.) =urifs= An automounter for the internet. Needs sshfs, curlftpfs and httpfs2, and allows URLs to be used as filenames.

fuse-bits release 2:

• Source code (ready to run): $webfile{fuse-bits-2.tar.gz,tar.gz}