[PATCH] make the doc of pipefail clear

[PATCH] make the doc of pipefail clear

[Han Pingtian]

Hi, 

I think we can make the doc of pipefail more clear with this patch:



If set, pipe will return non-zero if any element return non-zero.
Otherwise, pipe will return zero.

Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com>
---
 Doc/Zsh/options.yo | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Doc/Zsh/options.yo b/Doc/Zsh/options.yo
index 19920ca..cdfe46e 100644
--- a/Doc/Zsh/options.yo
+++ b/Doc/Zsh/options.yo
@@ -1743,8 +1743,8 @@ item(tt(PIPE_FAIL))(
 By default, when a pipeline exits the exit status recorded by the shell
 and returned by the shell variable tt($?) reflects that of the
 rightmost element of a pipeline.  If this option is set, the exit status
-instead reflects the status of the rightmost element of the pipeline
-that was non-zero, or zero if all elements exited with zero status.
+is non-zero if there was one element in the pipeline who exited with
+non-zero status, or zero if all elements exited with zero status.
 )
 pindex(SOURCE_TRACE)
 pindex(NO_SOURCE_TRACE)
-- 
1.9.3

Re: [PATCH] make the doc of pipefail clear

[Bart Schaefer]

On Apr 10,  9:16am, Han Pingtian wrote:
} 
} I think we can make the doc of pipefail more clear with this patch:

It might be more clear, but it's less correct.

Given

    setopt pipefail
    ( exit 1 ) | ( exit 2 ) | ( exit 3 ) | ( exit 4 ) | ( exit 0 )

the original doc fully describes that the exit status of the entire
pipeline is 4, whereas your change only states that it is "non-zero".

That part about "the rightmost" that you removed, is important.

Re: [PATCH] make the doc of pipefail clear

[Han Pingtian]

On Thu, Apr 09, 2015 at 06:53:38PM -0700, Bart Schaefer wrote:
> On Apr 10,  9:16am, Han Pingtian wrote:
> } 
> } I think we can make the doc of pipefail more clear with this patch:
> 
> It might be more clear, but it's less correct.
> 
> Given
> 
>     setopt pipefail
>     ( exit 1 ) | ( exit 2 ) | ( exit 3 ) | ( exit 4 ) | ( exit 0 )
> 
> the original doc fully describes that the exit status of the entire
> pipeline is 4, whereas your change only states that it is "non-zero".
> 
> That part about "the rightmost" that you removed, is important.

Thanks. Now I understand the original document ...