Background jobs and notification (stdout vs stderr)

Background jobs and notification (stdout vs stderr)

[Vincent Lefevre]

Let's consider:

greux:~> sleep 2&
[1] 20823
greux:~>
[1]  + done       sleep 2
greux:~>

The "[1] 20823" line is sent to stderr, whereas the "[1]  + done ..."
line is sent to stdout (I could see that with the coloring of stderr).
Is there any reason?

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
100% validated (X)HTML - Acorn / RISC OS / ARM, free software, YP17,
Championnat International des Jeux Mathématiques et Logiques, etc.
Work: CR INRIA - computer arithmetic / SPACES project at LORIA

Re: Background jobs and notification (stdout vs stderr)

[Peter Stephenson]

Vincent Lefevre wrote:
> Let's consider:
> 
> greux:~> sleep 2&
> [1] 20823
> greux:~>
> [1]  + done       sleep 2
> greux:~>
> 
> The "[1] 20823" line is sent to stderr, whereas the "[1]  + done ..."
> line is sent to stdout (I could see that with the coloring of stderr).
> Is there any reason?

Asynchronous notifications are currently set up to go direct to the
terminal.  It's actually the duplicated fd used for terminal handling
rather than stdout, but they're typically the same unless you try to
redirect stdout.

I think this is probably because you don't usually want asynchronous job
notifications mixed in with other error text, since they're nothing to
do with what's actually running: job control is specifically interactive.
Note that the interaction with the terminal output is inevitable, that's
why you get the editing buffer cleard and the prompt reprinted
afterwards.  I don't think you can redirect them without messing up
terminal editing.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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Re: Background jobs and notification (stdout vs stderr)

[Vincent Lefevre]

On 2004-07-02 14:16:33 +0100, Peter Stephenson wrote:
> I think this is probably because you don't usually want asynchronous job
> notifications mixed in with other error text, since they're nothing to
> do with what's actually running: job control is specifically interactive.
> Note that the interaction with the terminal output is inevitable, that's
> why you get the editing buffer cleard and the prompt reprinted
> afterwards.  I don't think you can redirect them without messing up
> terminal editing.

OK. I think that the zsh man pages should mention where all the data
output by zsh are sent (to stdout, stderr, the tty...).

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
100% validated (X)HTML - Acorn / RISC OS / ARM, free software, YP17,
Championnat International des Jeux Mathématiques et Logiques, etc.
Work: CR INRIA - computer arithmetic / SPACES project at LORIA