[PLUG] Re: dynamic file (script output)

[gabriel rosenkoetter <gr@eclipsed.net>]

On Sun, Nov 19, 2000 at 06:54:54PM -0500, MaD dUCK wrote:
> i need to create a dynamic file in that a read of the file through
> something like 'cat' will actually execute a script and pretend that
> the script's output to stdout is the actual file data. i tried using a
> FIFO, but there is no easy and reliable way to have the pipe filled
> with the output of exactly one program invocation, no more and no
> less.
> 
> so if i have a file i.e. /tmp/date linked in this way to /bin/date, i
> want the output from the date program when doing a 'cat /tmp/date'.
> 
> any ideas?

As I told you earlier, Martin, the Gnu HURD can do this, as any file
can be linked to an execution of X, where X can be pretty much
anything (well, that's executable, I guess).

The problem isn't the OS at large, it's specifically file system.
None of ext2fs, ffs, ufs, lfs, or any of the journaling (you call
it journaling, I call it log-structured, whatever) file systems in
the pipeline for Linux have this capability.

If you really want it, grab the ext2fs source, the Gnu HURD fs
source, splice the functionality in, and release it. (Actually not
as much work as it sounds like, I don't think, though definitely
non-trivial.)

       ~ g r @ eclipsed.net


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