bug in zsh-2.6-beta21

bug in zsh-2.6-beta21

[Vincent Lefevre]

I've just installed zsh 2.6-beta21 and found the following bug:

Under zsh 2.6-beta20:

$ var=`echo "ab\ncd\nef"`
$ echo $var
ab
cd
ef
$ var=`echo "ab\ncd\nef\n"`
$ echo $var
ab
cd
ef

$

This is OK. But under zsh 2.6-beta21:

$ var=`echo "ab\ncd\nef"`
$ echo $var
ab
cd
ef
$ var=`echo "ab\ncd\nef\n"`
$ echo $var
ab
cd
ef
$

The last "\n" is not printed.

Regards,

Vincent Lefevre.

Re: bug in zsh-2.6-beta21

[Zoltan Hidvegi]

Vincent Lefevre wrote:
> [...] But under zsh 2.6-beta21:
> 
> $ var=`echo "ab\ncd\nef"`
> $ echo $var
> ab
> cd
> ef
> $ var=`echo "ab\ncd\nef\n"`
> $ echo $var
> ab
> cd
> ef
> $
> 
> The last "\n" is not printed.

All other shells strip trailing newlines from command substitution and
POSIX requires this behaviour.  So far zsh stripped only one trailing
newline now it strips all.  But if the opposition of this change is big
enough I may change it back.  I thought that this change will be mostly
unnoticeable and I hope that it won't break any scripts.

Zoltan

Re: bug in zsh-2.6-beta21

[Vincent Lefevre]

Thanks for the information.

I wanted to "evaluate a variable with echo", e.g. to replace "\n" with
a newline character... I had something like this:
a="blah\nblah\n"
b=`echo $a`

With zsh 2.6-beta21, I changed the second line:
b=`echo ${a}+`
and I use $b[1,-2] instead of $b.

With this method, the last "\n" is not stripped.
Is there a better (recommended) method to do this?

Vincent Lefevre.

Re: bug in zsh-2.6-beta21

[Barton E. Schaefer]

On Jun 25,  9:11pm, Zoltan Hidvegi wrote:
} Subject: Re: bug in zsh-2.6-beta21
}
} All other shells strip trailing newlines from command substitution and
} POSIX requires this behaviour.  But if the opposition of this change is
} big enough I may change it back.

I think it's fine the way it is now.

-- 
Bart Schaefer                     Vice President, Technology, Z-Code Software
schaefer@z-code.com                   Division of NetManage Corporation
http://www.well.com/www/barts           http://www.ncdsoft.com/ZMail/