🚀 go-pugleaf

In <9208312221.AA21541@igc.apc.org> scott@igc.apc.org (Scott Weikart) writes:

| >Its SOP for shells that when a control statement has I/O redirected

| This is not true, in general (last week I wrote a program to test it).

| Redirecting stdin or stdout to files doesn't result in use of a sub-shell;

My definition of "SOP for shells" is what the Bourne shell does (and
when it matters, often the 7th edition Bourne shell).

Here's a simple test using /bin/sh

munnari$ f=0
munnari$ for i in a b
> do
> f=1
> done
munnari$ echo $f
1
munnari$  for i in a b
> do
> f=2
> done </dev/null
munnari$ echo $f
1

The point was that in general its unsafe to assume that a "sh"
type shell will allow you to alter the shell environment in any
way if I/O to a control statement is redirected at all.

Some shells may be more liberal in what they allow.  Personally
I don't think I'll be writing many scripts that depend on which version
of which shell I happen to be using.

kre