Re: set -e in bash 4

[Tobias Poschwatta]

On Wed, Oct 21, 2009 at 10:19:52AM +0100, Marc Herbert wrote:
> Tobias Poschwatta a écrit :
> > In the following test case test1.sh, bash 4 behaves differently from
> > bash 3.1. The behaviour of bash 3.1 is what I would expect to be
> > correct.  Is this a bug in bash 4 or an intentional change?
> 
> Isn't this related to this change?
> http://thread.gmane.org/gmane.comp.shells.bash.bugs/13465

Thanks for the link, but I don't think it is related.

I understand that the presence of || resets errexit for the subshell
in:

$ cat a.sh 
set -e
( echo 1; false; echo 2 ) || echo failed
echo done

$ /bin/bash a.sh
1
2
done


To get errexit in the subshell, I tried to enable it inside the
subshell:

$ cat b.sh
( set -e; echo 1; false; echo 2 ) || echo failed
echo done

$ /bin/bash b.sh
1
2
done


But 'set -e' inside the subshell has no effect. So, I tried to replace
|| with a test of $? which finally worked (but only if errexit is
disabled outside the subshell).

$ cat c.sh
( set -e; echo 1; false; echo 2 )
[ $? -eq 0 ] || echo failed
echo done

$ /bin/bash c.sh
1
failed
done


I find this very counterintuitive, and wonder if it's really the
correct behavior.

Thanks,
Tobias