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Check if PID exists

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# 8  
Old 03-11-2013
Try with awk then..

Code:
ps -ef | awk '$2==15160'

This User Gave Thanks to pamu For This Post:
mohtashims
# 9  
Old 03-11-2013
If your OS has the /proc filesystem (most modern ones do) you can also test like this

Code:
if [ -d /proc/$PID]
then
      echo "Process is still running"
else
     echo "Process has stopped"
fi

Edit: above withdrawn, (HP-UX dosn't have /proc). You could get ps to check for you:
Code:
if ps -p $PID > /dev/null 2>&1
then
    echo "Process is still running"
else
    echo "Process has stopped"
fi

Last edited by Chubler_XL; 03-11-2013 at 12:49 PM..
This User Gave Thanks to Chubler_XL For This Post:
alister
# 10  
Old 03-11-2013
Assuming the variable pid contains your pid and the user that executes the command has the right privileges:
Code:
kill -0 $pid 2>/dev/null && 
  printf '%d exists\n' $pid || 
    printf '%d does not exist\n' $pid

This User Gave Thanks to radoulov For This Post:
alister
# 11  
Old 03-11-2013
Quote:
Originally Posted by Chubler_XL
Code:
if ps -p $PID > /dev/null 2>&1
then
    echo "Process is still running"
else
    echo "Process has stopped"
fi

In my opinion, if existence is all that's to be tested, this is by far the sanest suggestion in this thread. There's no point in generating extensive ps output only to search for something that was already known before ps was invoked (the pid).

radoulov's suggestion should be used, however, if what really matters is whether or not a process can be terminated by the effective user id running the shell script.

Regardless, there's no need for any ps | [grep | awk] pipelines.

Regards,
Alister
# 12  
Old 03-11-2013
HI u can use below idea

please use correct syntax below may not be excat sytntax but u will get and idea
Code:
c=`ps -ef | grep exactprocessname | grep -v grep|wc -l`

if [ c -gt 0 && c -lt 1 ]

echo "process is running"

elif

if [ c -gt 1]

echo "multiple instances of process running"

else
echo "processs not running"
fi

Last edited by zozoo; 03-11-2013 at 04:39 PM..
# 13  
Old 03-11-2013
Quote:
Originally Posted by zozoo
HI u can use below idea

please use correct syntax below may not be excat sytntax but u will get and idea
Code:
c=`ps -ef | grep exactprocessname | grep -v grep|wc -l`

That can't be used because what is given is the pid and not the process name. And, even if what was known were the process name, that approach leaves the door open to false positives, for example, if the process name matches a user name or an argument name, or matches some other field in the ps output. If process name were the key, pgrep is the best solution.

The suggestion in post #2 is similarly deficient.

Regards,
Alister
Last edited by alister; 03-11-2013 at 04:56 PM..
# 14  
Old 03-11-2013
Since pid is reused, it is better to look for having a log file open using fuser. The pid could exit and the new pid assigned to another process of yours that has nothing to do with the application. Check not only the pid and user but the application, at least.
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