Re: Reading line by line

[Micah Cowan <micah@xxxxxxxxxx>]

Stephane Chazelas wrote:
> On Wed, Apr 11, 2007 at 11:52:41AM -0700, Micah Cowan wrote:
> [...]
> > $ echo 'a   b' | read -r
> >
> > zsh will preserve all whitespace between a and b, whereas other shells 
> > will condense it to a single space. POSIX states that, after splitting 
> > the fields, if there is only one variable name left in the args, all 
> > remaining fields will be assigned to that variable, with "their 
> > intervening separation", which IMO is difficult to interpret as anything 
> > other than the original separation that had been encountered.
> [...]
>
> No, you must have been confused by word splitting occuring upon
> unquoted variable expansions.

Perhaps. I could've sworn I'd quoted it... but now that I think about 
it, I probably used OP's example, which has it unquoted.

> echo 'a  b' | read a
> echo "$a"
>
> outputs "a  b"
>
> That's what POSIX requires and that's how zsh behaves when
> in POSIX emulation.

Right; I was talking about bash, dash and ksh behavior not being 
compliant, not zsh. But, if I did indeed leave it unquoted, that would 
explain the difference, since zsh, by default, does not field-split 
unquoted variables.

> Note that word splitting is not the only thing performed by
> POSIX shells upon variable expansion, there's also filename
> generation. That's why one should *NEVER* leave variables
> unquoted in POSIX scripts.

Agreed, absolutely. Well... s/*NEVER*/only when you know that word 
expansion is actually what you really want/

--
Micah J. Cowan
Programmer, musician, typesetting enthusiast, gamer...
http://micah.cowan.name/