How secure are shell scripts? (summary)

[Jay Maynard]

In article <7937 at star.cs.vu.nl> maart at cs.vu.nl (Maarten Litmaath) writes,
about secure alternatives to setuid shell scripts:
>	- acquire a UNIX version that's got the /dev/fd driver and uses
>	  that to launch the script.

This is a new one on me. What's /dev/fd supposed to do (on those systems where
it's not a floppy disk device), and, if the driver's available somewhere,
where can it be obtained?
-- 
Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can
jmaynard at thesis1.hsch.utexas.edu  | adequately be explained by stupidity.
"It's a hardware bug!" "It's a    +---------------------------------------
software bug!" "It's two...two...two bugs in one!" - _Engineer's Rap_