Shell Programming and Scripting

#!/bin/ksh

# edii_pid is PID of process to monitor.

# Checking if pid is listed in hosts processes.
# tr used for getting rid of potential leading blanks.
edii_pid_listed=`ps -p ${edii_pid} -o pid | grep -v "^  PID" | tr -d ' '`

if [[ ${edii_pid_listed} != ${edii_pid} ]]; then
  # So PID is listed, exists. In fact the process/application is runnig
  # for several days continuously.

  # Checking if pid is in running (=0) state.
  # tr used for getting rid of potential leading blanks.
  edii_pid_runnning=`ps -p ${edii_pid} -o s | grep -v "^S" | tr -d ' '`
  if [[ ${edii_pid_runnning} != 'O' ]]; then
    print "${edii_pid} isn't in running (O) state but ${edii_pid_runnning}!" 
  fi
fi

PID 2939 isn't in running (O) state but !

# the 0 is a zero and does not harm the process, you have to be root or same user
# to signal any process
   kill 0 $pid && echo "$pid is alive" || echo "$pid is not alive"

edii_pid_runnning=`ps -p ${edii_pid} -o s`
edii_pid_runnning_state=`echo ${edii_pid_runnning} | grep -v "^S" | tr -d ' '`
if [[ ${edii_pid_runnning_state} != 'O' ]]; then
    print "${edii_pid} isn't in running (O) state but is ${edii_pid_runnning}!" 
fi

edii_pid_runnning=`ps -p ${edii_pid} -o s=`

edii_pid_listed=`ps -p ${edii_pid} -o pid=`

if [[ ${edii_pid_listed} != ${edii_pid} ]]; then

if [[ -d /proc/${edii_pid} ]]; then
 echo "still alive"
else
 echo "dead"
fi

ps $pid >/dev/null 2>/dev/null || echo "$pid is dead"