[9fans] process group, processes running in the background

[9fans] process group, processes running in the background

[Rudolf Sykora]

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Hello,

is there any simple way how to identify processes belonging to one concrete
process group?

Is there any simple way how to change a process' group?

Is there anything like pstree in plan9?

Thanks
Ruda

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Re: [9fans] process group, processes running in the background

[Rudolf Sykora]

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And the last question should have been:

Can I say what processes are running in the background (only the last one
run is in $apid) and is it possible to get them back to foreground?

R.

2008/6/20 Rudolf Sykora <rudolf.sykora@gmail.com>:

> Hello,
>
> is there any simple way how to identify processes belonging to one concrete
> process group?
>
> Is there any simple way how to change a process' group?
>
> Is there anything like pstree in plan9?
>
> Thanks
> Ruda
>

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Re: [9fans] process group, processes running in the background

[a]

// Can I say what processes are running in the background...

I assume you mean in the shell (the rest of your questions were more
general). rc tracks this internally for wait to work (which will allow you
to wait for a given pid or all backgrounded pids) in waitpids in
/sys/src/cmd/rc/plan9.c, but i don't see that the contents of this are
exposed to users anywhere.

If one were sufficently motivated, it looks like it'd be fairly straight-
forward to add an env var, say apidlist, and have the *waitpid fns in
plan9.c manipulate it.

// ...is it possible to get them back to foreground?

Nope.
anthony

Re: [9fans] process group, processes running in the background

[Pietro Gagliardi]

On Jun 20, 2008, at 10:03 AM, Rudolf Sykora wrote:

> Hello,
>
> is there any simple way how to identify processes belonging to one
> concrete process group?

They're called "note groups" and the noteid file of each process has
the number. So if you call 6 lines of rc and 5 lines of awk simple,
then yes!

{
	for(i in /proc/*)
		if(! ~ $i /proc/trace)
			echo `{cat $i/noteid}:`{basename $i}
} | sort -t: -n | awk '
# based on squash by jon bentley from programming pearls 1st edition
BEGIN { FS = ":" }
$1 != prev { prev = $1; if(NR > 1) printf "\n"; printf "%d: ", $1 }
{ printf "%d ", $2 }
END { printf "\n" }
'

> Is there anything like pstree in plan9?
Work with the code I gave you and /sys/src/cmd/ps.c.

Pietro

Re: [9fans] process group, processes running in the background

[erik quanstrom]

> If one were sufficently motivated, it looks like it'd be fairly straight-
> forward to add an env var, say apidlist, and have the *waitpid fns in
> plan9.c manipulate it.

byron's rc does this.  the variable is called $apids.
i don't recall ever wanting for this feature in rc.

- erik

Re: [9fans] process group, processes running in the background

[Russ Cox]

There is no "job control" in Plan 9.
Instead, there is a window system.

Draw two windows, and run one command
in each.  Then it is very easy to bring one or the
other command to the foreground by clicking
with the mouse in the associated window.

Russ


P.S.  Processes by group:

for(i in `{grep . /proc/*/noteid | sed 's!.*:!!' | sort -nu}){
	echo $i
	ps | grep -f <{
		grep -l ' '$i' ' /proc/*/noteid >[2]/dev/null |
		sed 's!/proc/!^[^ ]+ +!; s!/noteid! !'
	}
}

Re: [9fans] process group, processes running in the background

[Rudolf Sykora]

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Thanks for everybody's answers... :)
R.

2008/6/20 Pietro Gagliardi <pietro10@mac.com>:

> On Jun 20, 2008, at 10:03 AM, Rudolf Sykora wrote:
>
>  Hello,
>>
>> is there any simple way how to identify processes belonging to one
>> concrete process group?
>>
>
> They're called "note groups" and the noteid file of each process has the
> number. So if you call 6 lines of rc and 5 lines of awk simple, then yes!
>
> {
>        for(i in /proc/*)
>                if(! ~ $i /proc/trace)
>                        echo `{cat $i/noteid}:`{basename $i}
> } | sort -t: -n | awk '
> # based on squash by jon bentley from programming pearls 1st edition
> BEGIN { FS = ":" }
> $1 != prev { prev = $1; if(NR > 1) printf "\n"; printf "%d: ", $1 }
> { printf "%d ", $2 }
> END { printf "\n" }
> '
>
>  Is there anything like pstree in plan9?
>>
> Work with the code I gave you and /sys/src/cmd/ps.c.
>
> Pietro
>
>
>

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