Secure shell scripts (again, sorry)

[Stephen R. van den Berg]

Sorry to bring this up again, I know this was a major thread some months ago,
but, I skipped it then, and I discover now that I need the info after all.

So if someone could just email me a summary he may still have lying around.

I need to know if any shell script starting with these 2 lines:
#!/bin/sh
IFS=' \t\n'

is secure enough that it will *always* set IFS to the desired value.

Thanks anyway :-)
--
Sincerely,                 berg at marvin.e17.physik.tu-muenchen.de
           Stephen R. van den Berg.
"I code it in 5 min, optimize it in 90 min, because it's so well optimized:
it runs in only 5 min.  Actually, most of the time I optimize programs."