News Group Posts

return value within pipeline pipe

Subject: Re: stderr stdout and return values
References: <d68e2226.0306040537.c6d92fa@posting.google.com>
<20030604142020.GB22521@jpradley.jpr.com>
<d68e2226.0306040911.49a54cf0@posting.google.com> 
From: spcecdt@deeptht.armory.com (John DuBois)
Date: 04 Jun 2003 18:25:32 GMT

JWR <no_spam_please@lycos.co.uk> wrote:
> On behalf of a colleague, we are trying to capture the return value in
> a script whilst having stderr and stdout returned to the screen and to
> a file. Example below:
> 
> # cat test
> a="fred
> echo$a
> # ./test 2>&1 | tee file
> ./test: syntax error at line 1 : `"' unmatched
> # echo $?
> 0
> # cat file
> ./test: syntax error at line 1 : `"' unmatched
> #
> 
> Now obviously we have the error to screen and file but the return
> value after echo $? is returning that our commands at the prompt were
> successful but we need it to return that the script 'test' failed.
...
>I want to capture the return value of the ./test command regardless of
>failure or not, but all we can get is the return value of tee.  We
>need to capture the stderr and sdtout and return value of ./test, and
>once with have worked out all the syntax we can incorporate the
>commands in a script which relies on the return value.  Thanks

Some solutions:

$ result=`exec 3>&1; { ./test 2>&1; echo $? >&3; } | tee file`
$ echo $result
1

In ksh:

$ ./test 2>&1 |&
$ pid=$!
$ tee file <&p
$ wait $!
$ echo $?
1

In bash:
$ ./test 2>&1 | tee file
$ echo ${PIPESTATUS[0]}
1


        John
-- 
John DuBois  spcecdt@armory.com  KC6QKZ/AE  http://www.armory.com/~spcecdt/

Comments?

Jump to Comments

Many of the products and books I review are things I purchased for my own use. Some were given to me specifically for the purpose of reviewing them. I resell or can earn commissions from the sale of some of these items. Links within these pages may be affiliate links that pay me for referring you to them. That's mostly insignificant amounts of money; whenever it is not I have made my relationship plain. I also may own stock in companies mentioned here. If you have any question, please do feel free to contact me.

Specific links that take you to pages that allow you to purchase the item I reviewed are very likely to pay me a commission. Many of the books I review were given to me by the publishers specifically for the purpose of writing a review. These gifts and referral fees do not affect my opinions; I often give bad reviews anyway.

We use Google third-party advertising companies to serve ads when you visit our website. These companies may use information (not including your name, address, email address, or telephone number) about your visits to this and other websites in order to provide advertisements about goods and services of interest to you. If you would like more information about this practice and to know your choices about not having this information used by these companies, click here.