ERRO: Lista de IDs de processo deve seguir -p

Question

Estou recebendo a seguinte mensagem de erro

Checking /var/www/integration-report.com/dist/server/app.js status:

ERROR: List of process IDs must follow -p.
********* simple selection *********  ********* selection by list *********
-A all processes                      -C by command name
-N negate selection                   -G by real group ID (supports names)
-a all w/ tty except session leaders  -U by real user ID (supports names)
-d all except session leaders         -g by session OR by effective group name
-e all processes                      -p by process ID
                                      -q by process ID (unsorted & quick)
T  all processes on this terminal     -s processes in the sessions given
a  all w/ tty, including other users  -t by tty
g  OBSOLETE -- DO NOT USE             -u by effective user ID (supports names)
r  only running processes             U  processes for specified users
x  processes w/o controlling ttys     t  by tty
*********** output format **********  *********** long options ***********
-o,o user-defined  -f full            --Group --User --pid --cols --ppid
-j,j job control   s  signal          --group --user --sid --rows --info
-O,O preloaded -o  v  virtual memory  --cumulative --format --deselect
-l,l long          u  user-oriented   --sort --tty --forest --version
-F   extra full    X  registers       --heading --no-heading --context
                                      --quick-pid
                    ********* misc options *********
-V,V  show version      L  list format codes  f  ASCII art forest
-m,m,-L,-T,H  threads   S  children in sum    -y change -l format
-M,Z  security data     c  true command name  -c scheduling class
-w,w  wide output       n  numeric WCHAN,UID  -H process hierarchy
Not running

quando executo o seguinte código

 echo -e "Checking $SERVER status:\n"
                PID='ps -aefw | grep "$DAEMON $SERVER" | grep -v " grep " | awk '{print $2}''
                if  ps -p $PID >&- ; then
                        echo "Running with PID $PID"
                else
                        echo "Not running"
                fi

Mas não entendo o erro real. Alguém pode me explicar melhor e me ajudar a resolver o problema?