While do test issue

[venhart]

Hi,

Please can someone advise what I'm doing wrong with my "while do done" loop ?

My first script Setup_A.ksh runs and when it has finished and the PID = 0, I need it to start my second script BatchRun.pl. Please see my while do done loop.

See below for details :


./Setup_A.ksh

typeset -i PID

PID=`ps -ef | grep Setup_A.ksh | wc -l`

while [ $PID > 0 ]
do
echo "Setup_A PID is running = $PID"
sleep 60

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

done

echo "Setup_A.ksh completed"

./BatchRun.pl

thank you

[Krendoshazin]

I suspect that part of the problem is that PID will always return 1, and therefore it never reaches the line to execute the bash script.

ps -ef | grep Setup_A.ksh
1002     24018 21088  0 06:22 pts/10   00:00:00 grep Setup_A.ksh

If you grep the output for Setup_A.ksh, then grep will return its own process which is currently searching for Setup_A.ksh.

Try 'ps -ef | grep Setup_A.ksh | grep -v grep | wc -l' instead:

ps -ef | grep Setup_A.ksh | grep -v grep | wc -l
0

I made a quick example. On my machine Setup_A.ksh will not be found and therefore execute the scipt I have specified:

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

while [ $PID != 0 ]
do
        echo "Setup_A PID is running = $PID"
        sleep 60

        PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`
done

sh new.sh

and the output:

krendoshazin@null:~>sh new1.sh
this is new.sh

[venhart]

Hi,

I have just tried this on my environment, and it does not start the second script "BatchRun.pl
" even when the PID = 0

This is my code :

#!/bin/sh

./Setup_A.ksh

typeset -i PID

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

while [ $PID > 0 ]
do
echo "Setup_A PID is running = $PID"
sleep 60

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

done

echo "Setup_A.ksh completed"

./BatchRun.pl


Is there something else I'm doing wrong within this while do done loop ?

thank you

[Krendoshazin]

Is there something else I'm doing wrong within this while do done loop ?

Yes, in my example I changed while [ $PID > 0 ] to while [ $PID != 0 ].

[atreyu]

Does that first script automatically go into the background somehow?

I'd do it something like this:

#!/bin/sh

echo "running Setup_A script:"
./Setup_A.ksh & while ps -p $! >/dev/null 2>&1; do
  echo script still running...
  sleep 1
done
echo done

./Setup_B.ksh

[scathefire]

If you are going to call a PERL script inside of shell script, you may need to point it to the PERL executable:

/usr/bin/perl /path/to/perl/script

I cannot speak for Korn Shell, but I know Bash shells have this issue (for me at least).

[atreyu]

@scathefire,
jc, do u have that issue even when the perl script is executable and it has the correct path to the command line interpreter (e.g., #!/usr/bin/perl)?

[venhart]

your version does not work for me. As the script run's in backgroud and start's multiple pids. So the first intial pid finishes and goes to the next script. But I need all the pids to complete before it starts the second script.

Also tried the orginal reply :

Yes, in my example I changed while [ $PID > 0 ] to while [ $PID != 0 ].

This did not work for me either ??

At present my script looks like ;

#!/bin/sh

./Setup_A.ksh

typeset -i PID

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

while [ $PID != 0 ]
do
echo "Setup_A PID is running = $PID"
sleep 60

PID=`ps -ef | grep Setup_A.ksh | grep -v grep | wc -l`

done

echo "Setup_A.ksh completed"

./BatchRun.pl

[scathefire]

@scathefire,
jc, do u have that issue even when the perl script is executable and it has the correct path to the command line interpreter (e.g., #!/usr/bin/perl)?

Yeah for some reason it was always easier to execute shell scripts in perl with system() or exec() than it was to execute perl scripts from a shell script.

[atreyu]

Not clear to me: does Setup_A.ksh spawn sub-shells or programs, then?

Maybe something like this would work...

#!/bin/bash
./Setup_A.ksh&
mainpid=$!
progpid=$$

get_pids(){
  pids=$(ps -o pid,cmd|grep $0|grep -v $progpid)
}
get_pids
until [ -z "$pids" ]; do
  echo still running..
  sleep 1
  get_pids
  ps -eo pid,ppid,cmd|grep $0|awk "\$1 !~ /$progpid/"|grep -q . || unset pids
done