Program-invoking Symbolic Links?

[John M Collins <jmc@xisl.com>]

(Please CC any reply to jmc AT xisl.com as I'm not subbed - thanks).

I wondered if anyone had ever thought of implementing an alternative form of 
symbolic link which was in fact an invocation of a program?

Such a symbolic link would "do all the necessary" to fork off a new process 
running the specified program with input or output from or to a pipe 
depending on whether the link was opened for writing or reading respectively. 
RW access would probably have to be banned and the link would usually be 
read-only or write-only.

What I originally wanted was symbolic links (with "=>" as a possible 
notation).

latest_version.tar => "tar cf - /latest/and/greatest"
latest_version.tgz => "gzip -c latest_version"

and the like, which I could link on a website so I didn't have to run around 
updating tar files/zip files/gzipped tar files etc each time I fix a bug in 
some package.

Such a scheme would let you implement things like hit counts on web sites "for 
free" without you having to rush out and run a CGI program as at present.

Obviously, a whole lot of semantics and options for signal handling $PATH name 
search etc would have to be built into the kernel (or possibly handled like 
ld-nnn.so), but the idea would seem to me to close one arguable "lack of 
orthogonality" between files and pipes.

You could argue that /proc is halfway there - I'd just like a user-specific 
version.

-- 
John Collins Xi Software Ltd www.xisl.com