Re: [Help-bash] Use pid of cmd run in sub shell in parent shell?

[Patrick Schleizer]

Greg Wooledge:
> On Thu, May 01, 2014 at 07:46:29PM +0000, Patrick Schleizer wrote:
>> while read line; do
>>    log "...: $line"
>> done < <(
>>    {
>>       long_running_cmd_here
>>    }
>> ) &
>>
>> echo "Need pid of long_running_cmd_here here."
>>
>> =====
>>
>> I need the pid of long_running_cmd_here for job control, so I can send
>> signals to long_running_cmd_here.
> 
> When you need finer control than <(...) allows, you must set it aside
> and use a named pipe.
> 
> fifo=${TMPDIR:-/tmp}/myscript.$$
> trap 'rm -f "$fifo"' EXIT
> mkfifo "$fifo" || exit
> { long_running_cmd; } > "$fifo" & pid=$!
> while read line; do ...; done < "$fifo"
> 
> <(...) is just a shortcut, and sometimes shortcuts don't let you do what
> you need.

I had to add a "&" behind "done < "$fifo" to make that non-blocking as well.
As well as to implement a sigterm trap inside the subshell.

Works great. Thank you, Greg for your help!

Cheers,
Patrick