Re: reading from external command

[Alex fxmbsw7 Ratchev]

here with coproc as transmittler instead of a temp file

bash peng2.

pid 15200 exit 4
pid 15201 exit 1
pid 15202 exit 2
pid 15203 exit 3


#!/bin/bash

 p() {
printf $BASHPID\\n >&${mix[1]}
 }

  coproc mix \
 while read -r in ; do
[[ $in == [!0-9] ]] && exec printf %d\\n ${pids[@]} ||
pids+=( $in )
 done

 while read -r r ; do
: <( p ; exit $r )
 done < <( p ; printf 1\\n2\\n3\\n ; exit 4 )

 for p in $( printf q\\n >&${mix[1]} ; cat <&$mix ) ; do
wait $p
printf 'pid %d exit %d\n' $p $?
 done

exit

On Fri, Apr 1, 2022 at 1:52 AM Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
wrote:
>
> sorry again i try..
>
> bash peng2
>
> pid 14608 exit 4
> pid 14609 exit 1
> pid 14610 exit 2
> pid 14611 exit 3
>
>
> cat peng2
>
> #!/bin/bash
>
>  p() {
> printf $BASHPID\\n >>/tmp/ap
> }
>
> >/tmp/ap
>
>  while read -r r ; do
> : <( p ; exit $r )
>  done < <( p ; printf 1\\n2\\n3\\n ; exit 4 )
>
>  while read -r p ; do
> wait $p
> printf 'pid %d exit %d\n' $p $?
>  done </tmp/ap
>
> rm -f /tmp/ap
>
> On Fri, Apr 1, 2022 at 1:45 AM Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
wrote:
>>
>> i did
>>
>> with printf $BASHPID
>>
>> bye
>>
>> On Fri, Apr 1, 2022 at 1:41 AM Peng Yu <pengyu.ut@gmail.com> wrote:
>>>
>>> I don't get how to modify the while-loop (with unnamed pipes in the
>>> body) to get the exit code in the loop input unnamed pipe. Could you
>>> make it clear by showing a working example? Thanks.
>>>
>>> On 3/31/22, Chet Ramey <chet.ramey@case.edu> wrote:
>>> > On 3/30/22 6:32 PM, Peng Yu wrote:
>>> >> I am not sure how wait for "$!" would work robustly.
>>> >
>>> > You have to capture $! before it can be overwritten by another
command. For
>>> > instance, you can assign it to another variable.
>>> >
>>> >> In the following example, it can not get the error in the input.
>>> >
>>> > Because you didn't do that.
>>> >
>>> > --
>>> > ``The lyf so short, the craft so long to lerne.'' - Chaucer
>>> >                ``Ars longa, vita brevis'' - Hippocrates
>>> > Chet Ramey, UTech, CWRU    chet@case.edu
http://tiswww.cwru.edu/~chet/
>>> >
>>>
>>>
>>> --
>>> Regards,
>>> Peng