On Sat, Oct 04, 2003 at 04:50:47PM -0400, James K. Lowden wrote:
> $ ping -i 120 -o di |xmessage -file - &
> [4] 1305
> $ jobs -ls; ps -aux |egrep '^USER|130[45]'
> [4]+  1304 Stopped (tty output)    ping -i 120 -o di
>       1305                       | xmessage -file -
> USER       PID %CPU %MEM   VSZ   RSS TT STAT STARTED       TIME COMMAND
> jklowden  1305  0.0  0.0    24    28 p0 T     4:04PM    0:00.01 xmessage
> -file 
> root      1304  0.0  0.2   352   248 p0 T     4:04PM    0:00.01 ping -i
> 120 -o 
> 
> The machine "di" is down; I started the above poll to tell me when it
> comes back up.  But why is the job stopped?  I don't understand.  
> 
> "stopped" AIUI means ping, above, can't write to the tty.  I'm guessing it
> has something to do with the fact that ping is set-uid root, and job
> control doesn't have any way to write its output to my tty.  Except I'd
> expect ping's output to go to its stdout, which obviously is piped to
> xmessage.  And except that traceroute(8) is also set-uid and works fine. 
> So I think it's something special about ping.  

If di is down, ping may need to be able to print some error message to
stderr. You need to redirect stderr as well

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 24 ans d'experience feront toujours la difference
--