topic Re: why could not find process? in Operating System - Linux

why could not find process?

faust2008 — Thu, 20 Jul 2006 04:52:52 GMT

Hi , export,

My platform is hp 11i.
I user timer.sh to start a program timer 热repeatly. the content of timer.sh is:

while(true)
do
if [ "`ps -ef|grep './timer '|grep -v grep`" = "" ]
then
./timer IBSS2 WSNADRR=//132.97.9.71:2888 >/dev/null 2>&1
sleep 32
else
sleep 32
fi
done

I start timer.sh in this way:
ksh
timer.sh &
exit
but when I use ps -fe|grep timer.sh ,
I find nothing ,I think the timer.sh should stay alive all the time. in fact the timer exec repeatly.
can anyone tell me why ?
thx a lot

Re: why could not find process?

RAC_1 — Thu, 20 Jul 2006 05:03:53 GMT

Does your program (timer) start manually? Also, you check check if a processes is running or not by sending signal 0 to it.

Also, whay all that grep? If you know process name (exact process name), then you can do as follows.

proc_pid=$(UNIX95= ps -C "timer" -o pid|grep -v 'PID)

kill -o ${proc_pid} || "start_your_program"

Re: why could not find process?

Jonathan Fife — Thu, 20 Jul 2006 10:19:49 GMT

Does timer.sh invoke a new shell (ie. #!/bin/ksh)?

If not, it will just execute the contents of the script and not show the script name in a process list. If you do a ps -fe | grep sleep I bet you'll see your sleep 32 processes there.

$cat timer.sh
while(true)
do
sleep 5
done
$./timer.sh &
[1] 13012
$ps -ef | grep timer
fifejj 13016 12414 0 11:23:59 pts/ta 0:00 grep timer
$ps -ef | grep 13012
fifejj 13012 12414 1 11:23:55 pts/ta 0:00 -ksh
fifejj 13018 13012 1 11:24:00 pts/ta 0:00 sleep 5

and now invoking a new shell:

$cat timer.sh
#!/bin/ksh

while(true)
do
sleep 5
done
$./timer.sh &
[1] 13028
$ps -ef | grep timer
fifejj 13032 12414 1 11:24:28 pts/ta 0:00 grep timer
fifejj 13028 12414 3 11:24:26 pts/ta 0:00 /bin/ksh ./timer.sh

Re: why could not find process?

faust2008 — Fri, 21 Jul 2006 02:52:51 GMT

Jonathan, you are right , I can grep sleep 32. I just don't understand why can not grep
timer.sh
what is the diference betwen ksh and #!/bin/ksh?
if I use #!/bin/ksh , it seem that I can grep ./timer.sh ?

we have servral programs , all exex like
this :
ksh
program1 $
exit
ksh
program2 $
exit
I donot know why they exec like this.
can I exec them like this? :
#!/bin/ksh
program1 $
program2 $
exit
thanks a lot

Re: why could not find process?

Jonathan Fife — Fri, 21 Jul 2006 07:02:49 GMT

Putting #!/bin/ksh at the beginning of the script will just invoke a new shell. Otherwise, the commands will run in the current shell.

It should be fine to run them in an executable script as

#!/bin/ksh
program1
program2
exit

Jon