editing file in-place with '<>'

editing file in-place with '<>'

[Han Pingtian]

Hi,

I'm reading the guide and find it's not the case said in the guide page 132 about '<>' in-place editing.

% echo test > redirtest
% sed 's/e/Z/g' <> redirtest 1>&0
% cat redirtest
test
tZst

And looks like we can get the in-place editing by adding another '<> redirtest' in the end and turn off
multios:

% zsh -f 
localhost% unsetopt multios
localhost% echo test > redirtest
localhost% sed 's/e/Z/g' <> redirtest  1>&0 <> redirtest
localhost% cat redirtest
tZst
localhost%

So, it is the second '<> redirtest' reset the file offset of redirtest before sed outputs the result?

Re: editing file in-place with '<>'

[Peter Stephenson]

On Mon, 23 Jun 2014 16:06:08 +0800
Han Pingtian <hanpt@linux.vnet.ibm.com> wrote:
> I'm reading the guide and find it's not the case said in the guide
> page 132 about '<>' in-place editing.
> 
> % echo test > redirtest
> % sed 's/e/Z/g' <> redirtest 1>&0
> % cat redirtest
> test
> tZst

Yes, I get that too.  It's possible this worked at the time but the
internals have changed.  It's a long time since I wrote that and it
really seems it's a bit messy to advise users to do it that way.

pws