GNU bug report logs - #21919
tee enhancement

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "Tim Shaw" <timshaw <at> mail.usa.com>
To: bug-coreutils <at> gnu.org
Subject: tee enhancement
Date: Sat, 14 Nov 2015 17:00:30 +0100

[Message part 1 (text/html, inline)]

Message #8 received at 21919 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Tim Shaw <timshaw <at> mail.usa.com>, 21919 <at> debbugs.gnu.org
Subject: Re: bug#21919: tee enhancement
Date: Sun, 15 Nov 2015 23:59:55 +0000

On 14/11/15 16:00, Tim Shaw wrote:
> If I am using stdout redirection of a shell block to capture some text I am generating, errors need to go to stderr, but it would also be good if they went into the generated output. For example
> for i in files*; do
>   if there_is_an_error; then
>     echo big long complicated error message goes here >&2
>     echo big long complicated error message goes here
>     continue
>   fi
>    stuff_producing_text_on_stdout
> done > file_i_am_creating
>  
> I do not like duplicating code, such as the big long error message echo. So, I could create a temp file or a temp shell var to save the message, but that makes things more complicated than just duplicating the code, and also is just not my style for something transient like this.
>  
> What I would like to do is add a parameter to tee, "-2", that copies to stderr in addition to stdout, just like "-" copies to stdout twice. 

Note `tee -` now copies to a file called '-' rather than
duplicating to stdout, since v8.24 as discussed at:
http://lists.gnu.org/archive/html/coreutils/2015-02/msg00085.html

> So the code becomes
>     echo big long complicated error message goes here | tee -2
> Simple, eh?
>  
> Where's the tee source? I know this would not be POSIX compliant, but it would work for me, and I hate having to rewrite everything from scratch for trivial stuff like this.

Maybe shell constructs like this would suffice?

  { echo error | tee >(cat >&2); }

cheers,
Pádraig.

Message #11 received at 21919 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Tim Shaw <timshaw <at> mail.usa.com>, 21919 <at> debbugs.gnu.org
Subject: Re: bug#21919: tee enhancement
Date: Mon, 16 Nov 2015 00:23:38 +0000

tag 21919 notabug
close 21919
stop

On 15/11/15 23:59, Pádraig Brady wrote:
> On 14/11/15 16:00, Tim Shaw wrote:
>> If I am using stdout redirection of a shell block to capture some text I am generating, errors need to go to stderr, but it would also be good if they went into the generated output. For example
>> for i in files*; do
>>   if there_is_an_error; then
>>     echo big long complicated error message goes here >&2
>>     echo big long complicated error message goes here
>>     continue
>>   fi
>>    stuff_producing_text_on_stdout
>> done > file_i_am_creating
>>  
>> I do not like duplicating code, such as the big long error message echo. So, I could create a temp file or a temp shell var to save the message, but that makes things more complicated than just duplicating the code, and also is just not my style for something transient like this.
>>  
>> What I would like to do is add a parameter to tee, "-2", that copies to stderr in addition to stdout, just like "-" copies to stdout twice. 
> 
> Note `tee -` now copies to a file called '-' rather than
> duplicating to stdout, since v8.24 as discussed at:
> http://lists.gnu.org/archive/html/coreutils/2015-02/msg00085.html
> 
>> So the code becomes
>>     echo big long complicated error message goes here | tee -2
>> Simple, eh?
>>  
>> Where's the tee source?

tee source is at http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/tee.c

> I know this would not be POSIX compliant, but it would work for me, and I hate having to rewrite everything from scratch for trivial stuff like this.
> 
> Maybe shell constructs like this would suffice?
> 
>   { echo error | tee >(cat >&2); }

Or this is simpler:

  echo error | tee /dev/stderr

cheers,
Pádraig.

Message #14 received at 21919 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Tim Shaw <timshaw <at> mail.usa.com>, 21919 <at> debbugs.gnu.org
Subject: Re: bug#21919: tee enhancement
Date: Sun, 15 Nov 2015 17:28:08 -0800

Tim Shaw wrote:
>       echo big long complicated error message goes here | tee -2

How about "tee /dev/stderr" instead of a new option?  "tee /dev/stderr"  already 
works on many platforms now.  We could easily arrange for it to work on the 
remaining platforms where it does not already work.

Message #17 received at 21919 <at> debbugs.gnu.org (full text, mbox):

From: isabella parakiss <izaberina <at> gmail.com>
To: Tim Shaw <timshaw <at> mail.usa.com>
Cc: 21919 <at> debbugs.gnu.org
Subject: Re: bug#21919: tee enhancement
Date: Mon, 16 Nov 2015 02:22:33 +0100

On 11/14/15, Tim Shaw <timshaw <at> mail.usa.com> wrote:
> If I am using stdout redirection of a shell block to capture some text I am
> generating, errors need to go to stderr, but it would also be good if they
> went into the generated output. For example
> for i in files*; do
>   if there_is_an_error; then
>     echo big long complicated error message goes here >&2
>     echo big long complicated error message goes here
>     continue
>   fi
>    stuff_producing_text_on_stdout
> done > file_i_am_creating
>
> I do not like duplicating code, such as the big long error message echo. So,
> I could create a temp file or a temp shell var to save the message, but that
> makes things more complicated than just duplicating the code, and also is
> just not my style for something transient like this.
>
> What I would like to do is add a parameter to tee, "-2", that copies to
> stderr in addition to stdout, just like "-" copies to stdout twice. So the
> code becomes
>     echo big long complicated error message goes here | tee -2
> Simple, eh?
>
> Where's the tee source? I know this would not be POSIX compliant, but it
> would work for me, and I hate having to rewrite everything from scratch for
> trivial stuff like this.

tee /dev/stderr

---
xoxo iza

Message #20 received at 21919 <at> debbugs.gnu.org (full text, mbox):

From: Bernhard Voelker <mail <at> bernhard-voelker.de>
To: Tim Shaw <timshaw <at> mail.usa.com>, 21919 <at> debbugs.gnu.org
Subject: Re: bug#21919: tee enhancement
Date: Mon, 16 Nov 2015 08:06:18 +0100

On 11/14/2015 05:00 PM, Tim Shaw wrote:
> What I would like to do is add a parameter to tee, "-2", that copies to stderr in addition to stdout, just like "-"
> copies to stdout twice. So the code becomes
>     echo big long complicated error message goes here | tee -2
> Simple, eh?

Having an additional option to refer to a certain file descriptor
sounds worthwhile and tempting.  OTOH, you can already refer to
/dev/stderr as a file name for the 2nd file descriptor already
on many/most systems:

  echo big long complicated error message goes here | tee /dev/stderr

Does this work for you?

> Where's the tee source? I know this would not be POSIX compliant, but it would work for me, and I hate having to rewrite
> everything from scratch for trivial stuff like this.

http://git.savannah.gnu.org/cgit/coreutils.git/tree/README-hacking

Have a nice day,
Berny

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