Shell,根据进程pid结束该进程

#!/bin/sh 
PIDFILE=/tmp/app.pid  
echo 'Kill process from PID file'  
if test -f $PIDFILE  ; then  
    PID=`cat $PIDFILE`
    kill -3 $PID
    if kill -9 $PID ; then
        echo "process stopped"
    else
        echo "process could not be stopped"
    fi
    rm -f $PIDFILE
    f