Re: Bug in bash? different from ksh, at any rate...

On Sat, May 28, 2011 at 01:14:42AM -0700, Rick Thomas wrote:

Can anybody explain this difference between the behavior of bash and
ksh?

When reading the man page, I would expect both of them to have the
behavior exhibited by ksh.
Why does bash seem to treat "return" like a single level "break" in
this context?

The "echo "$AA" | while read" is important context. If I change it
to "for i in 0 1", return does as expected.

If it's any help, changing "return" to "break 2" doesn't help. with
bash, it still gives "1 1 1 1"
while ksh still gives "1"

I wonder if it has anything to do with "while read" causing a
subshell to be created, and bash getting confused about the "return"
inside of a subshell. If so, it's a bug in bash that ksh gets
right, so it ought to be fixable.

I can't reproduce it:

$ cat strange.sh
function strange {
for j in 0 1 2 3
do
AA=' 1
2'
echo "$AA" | while read i
do
echo "$i"
return
done
done
}
echo $(strange)

$ bash ./strange.sh
1 1 1 1

$ ksh ./strange.sh
1 1 1 1

ii bash 4.1-3 The GNU Bourne Again SHell
ii mksh 39.3.20100725-1 MirBSD Korn Shell

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