#!/usr/bin/env python #coding=utf8  from time import sleep import os  try: pid = os.fork() except OSError, e: pass  sleep(30)

[root@localhost ~]# python test2.py &[1] 2464[root@localhost ~]# ps -lF S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD4 S 0 2379 2377 0 80 0 - 28879 wait pts/1 00:00:00 bash0 S 0 2464 2379 0 80 0 - 31318 poll_s pts/1 00:00:00 python1 S 0 2465 2464 0 80 0 - 31318 poll_s pts/1 00:00:00 python0 R 0 2466 2379 0 80 0 - 37227 - pts/1 00:00:00 ps?

#-*- coding:utf-8 -*- from time import sleepimport os print('start+++++++++++++')#創(chuàng)建子進(jìn)程之前聲明的變量source = 10try:    pid = os.fork()    print('pid=',pid)    if pid == 0: #子進(jìn)程        print("this is child process.")        source = source - 1 #在子進(jìn)程中source減1    else: #父進(jìn)程        print("this is parent process." )    print(source)except (OSError,e):    passprint('END---------------')　　

[root@localhost ~]# python test3.pystart+++++++++++++pid= 2550this is parent process.10END---------------pid= 0this is child process.9END---------------?　　

def main():  ''' 程序要執(zhí)行的邏輯代碼 '''  pass  # 創(chuàng)建守護(hù)進(jìn)程函數(shù)def createDaemon():  ''' 第一塊（創(chuàng)建第一個(gè)子進(jìn)程） '''  # fork 第一個(gè)子進(jìn)程（如果fork成功，父進(jìn)程自殺，只留下第一個(gè)子進(jìn)程繼續(xù)向下運(yùn)行）  try:    if os.fork() > 0:      sys.exit(0)  except OSError, error:    print '（fork第一個(gè)子進(jìn)程失?。ゝork #1 failed: %d (%s)' % (error.errno, error.strerror)    sys.exit(1)  ''' 第一塊結(jié)束 '''   ######　第一個(gè)進(jìn)程創(chuàng)建成功后，它的ppid = 1，已是一個(gè)守護(hù)里程了，但有些功能上還是有被限制。  ######　所以下面再來(lái)創(chuàng)建一個(gè)子進(jìn)程。第二次創(chuàng)建的子進(jìn)程限制就沒那多了，有可能沒有，所以最安全。  ######　下面來(lái)創(chuàng)建第二個(gè)子進(jìn)程?！?   os.chdir('/')　# 把第一個(gè)子進(jìn)程的工作目錄切換到 / （根目錄）  os.setsid() # 第一個(gè)子進(jìn)程取得程序的權(quán)限  os.umask(0) # 第一個(gè)子進(jìn)程取得工作目錄的所有操作（目錄的rwx）    ''' 第二塊（創(chuàng)建第二個(gè)子進(jìn)程） '''  # fork 第二個(gè)子進(jìn)程（如果fork成功，第一個(gè)子進(jìn)程自殺，只留下新創(chuàng)建的第二個(gè)子進(jìn)程）  try:    pid = os.fork()    if pid > 0:      print 'Daemon PID %d' % pid      sys.exit(0)  except OSError, error:    print '（fork第二個(gè)子進(jìn)程失?。ゝork #2 failed: %d (%s)' % (error.errno, error.strerror)    sys.exit(1)  ''' 第二塊結(jié)束 '''    #######　通過上面兩個(gè) try 語(yǔ)句塊，只留下了第二個(gè)子進(jìn)程在運(yùn)行了。這時(shí)第二個(gè)子進(jìn)程的ppid=1。  #######　創(chuàng)建的第二個(gè)子進(jìn)程，可以說是一個(gè)不受限的守護(hù)進(jìn)程了。     # 重定向標(biāo)準(zhǔn)IO（因?yàn)橹挥械诙€(gè)子進(jìn)程在運(yùn)行了，所以也就是指定整個(gè)程序的輸入、輸出、錯(cuò)誤流）     # sys.stdout.flush() # 清除程序運(yùn)行空間的輸出流  # sys.stderr.flush()　# 清除程序運(yùn)行空間的錯(cuò)誤流   # inputS = file("/dev/null", 'r') 　# 定義一個(gè) inputS 文件對(duì)象  # outputS = file("/dev/null", 'a+')　# 定義一個(gè) outputS 文件對(duì)象  # errorS = file("/dev/null", 'a+', 0)　# 定義一個(gè) errorS 文件對(duì)象   # os.dup2(inputS.fileno(), sys.stdin.fileno()) # 把程序的輸入流重定向到上面定義的 inputS 文件對(duì)象上。  # os.dup2(so.fileno(), sys.stdout.fileno()) # 把程序的 輸出流 重定向到上面定義的 outputS 文件對(duì)象上。  # os.dup2(se.fileno(), sys.stderr.fileno()) # 把程序的 錯(cuò)誤流 重定向到上面定義的 errorS 文件對(duì)象上。   main() # main函數(shù)為真正程序邏輯代碼  if __name__ == "__main__":  if platform.system() == "Linux":      createDaemon()    else:      sys.exit()  　　

# coding: utf-8 import osimport sysimport timeimport atexitimport signal  class Daemon:  def __init__(self, pidfile='/tmp/daemon.pid', stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):    self.stdin = stdin    self.stdout = stdout    self.stderr = stderr    self.pidfile = pidfile   def daemonize(self):    if os.path.exists(self.pidfile):      raise RuntimeError('Already running.')     # First fork (detaches from parent)    try:      if os.fork() > 0:        raise SystemExit(0)    except OSError as e:      raise RuntimeError('fork #1 faild: {0} ({1})/n'.format(e.errno, e.strerror))     os.chdir('/')    os.setsid()    os.umask(0o22)     # Second fork (relinquish session leadership)    try:      if os.fork() > 0:        raise SystemExit(0)    except OSError as e:      raise RuntimeError('fork #2 faild: {0} ({1})/n'.format(e.errno, e.strerror))     # Flush I/O buffers    sys.stdout.flush()    sys.stderr.flush()     # Replace file descriptors for stdin, stdout, and stderr    with open(self.stdin, 'rb', 0) as f:      os.dup2(f.fileno(), sys.stdin.fileno())    with open(self.stdout, 'ab', 0) as f:      os.dup2(f.fileno(), sys.stdout.fileno())    with open(self.stderr, 'ab', 0) as f:      os.dup2(f.fileno(), sys.stderr.fileno())     # Write the PID file    with open(self.pidfile, 'w') as f:      print(os.getpid(), file=f)     # Arrange to have the PID file removed on exit/signal    atexit.register(lambda: os.remove(self.pidfile))     signal.signal(signal.SIGTERM, self.__sigterm_handler)   # Signal handler for termination (required)  @staticmethod  def __sigterm_handler(signo, frame):    raise SystemExit(1)   def start(self):    try:      self.daemonize()    except RuntimeError as e:      print(e, file=sys.stderr)      raise SystemExit(1)     self.run()   def stop(self):    try:      if os.path.exists(self.pidfile):        with open(self.pidfile) as f:          os.kill(int(f.read()), signal.SIGTERM)      else:        print('Not running.', file=sys.stderr)        raise SystemExit(1)    except OSError as e:      if 'No such process' in str(e) and os.path.exists(self.pidfile):        os.remove(self.pidfile)   def restart(self):    self.stop()    self.start()   def run(self):  #繼承類重寫該方法    pass

 #導(dǎo)入剛剛編寫的基類 from daemon import Daemon #繼承 class MyTestDaemon(Daemon): #重寫run方法,就是你要后臺(tái)運(yùn)行的函數(shù)   def run(self):   #后臺(tái)運(yùn)行的函數(shù),比如shell輸出到自己定義的文件     sys.stdout.write('Daemon started with pid {}/n'.format(os.getpid()))     while True:       sys.stdout.write('Daemon Alive! {}/n'.format(time.ctime()))       sys.stdout.flush()        time.sleep(5)  if __name__ == '__main__':   PIDFILE = '/tmp/daemon-example.pid'   LOG = '/tmp/daemon-example.log'   daemon = MyTestDaemon(pidfile=PIDFILE, stdout=LOG, stderr=LOG)    if len(sys.argv) != 2:     print('Usage: {} [start|stop]'.format(sys.argv[0]), file=sys.stderr)     raise SystemExit(1)    if 'start' == sys.argv[1]:     daemon.start()   elif 'stop' == sys.argv[1]:     daemon.stop()   elif 'restart' == sys.argv[1]:     daemon.restart()   else:     print('Unknown command {!r}'.format(sys.argv[1]), file=sys.stderr)     raise SystemExit(1)

# coding: utf-8import osimport sysimport timeimport atexitimport signalclass Daemon:  def __init__(self, pidfile='/tmp/daemon.pid', stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):    self.stdin = stdin    self.stdout = stdout    self.stderr = stderr    self.pidfile = pidfile  def daemonize(self):    if os.path.exists(self.pidfile):      raise RuntimeError('Already running.')    # First fork (detaches from parent)    try:      if os.fork() > 0:        raise SystemExit(0)    except OSError as e:      raise RuntimeError('fork #1 faild: {0} ({1})/n'.format(e.errno, e.strerror))    os.chdir('/')    os.setsid()    os.umask(0o22)    # Second fork (relinquish session leadership)    try:      if os.fork() > 0:        raise SystemExit(0)    except OSError as e:      raise RuntimeError('fork #2 faild: {0} ({1})/n'.format(e.errno, e.strerror))    # Flush I/O buffers    sys.stdout.flush()    sys.stderr.flush()    # Replace file descriptors for stdin, stdout, and stderr    with open(self.stdin, 'rb', 0) as f:      os.dup2(f.fileno(), sys.stdin.fileno())    with open(self.stdout, 'ab', 0) as f:      os.dup2(f.fileno(), sys.stdout.fileno())    with open(self.stderr, 'ab', 0) as f:      os.dup2(f.fileno(), sys.stderr.fileno())    # Write the PID file    with open(self.pidfile, 'w') as f:      print(os.getpid(), file=f)    # Arrange to have the PID file removed on exit/signal    atexit.register(lambda: os.remove(self.pidfile))    signal.signal(signal.SIGTERM, self.__sigterm_handler)  # Signal handler for termination (required)  @staticmethod  def __sigterm_handler(signo, frame):    raise SystemExit(1)  def start(self):    try:      self.daemonize()    except RuntimeError as e:      print(e, file=sys.stderr)      raise SystemExit(1)    self.run()  def stop(self):    try:      if os.path.exists(self.pidfile):        with open(self.pidfile) as f:          os.kill(int(f.read()), signal.SIGTERM)      else:        print('Not running.', file=sys.stderr)        raise SystemExit(1)    except OSError as e:      if 'No such process' in str(e) and os.path.exists(self.pidfile):         os.remove(self.pidfile)  def restart(self):    self.stop()    self.start()  def run(self):    pass

import osimport sysimport timefrom daemon import Daemonclass MyTestDaemon(Daemon):  def run(self):    sys.stdout.write('Daemon started with pid {}/n'.format(os.getpid()))    while True:      sys.stdout.write('Daemon Alive! {}/n'.format(time.ctime()))      sys.stdout.flush()      time.sleep(5)if __name__ == '__main__':  PIDFILE = '/tmp/daemon-example.pid'  LOG = '/tmp/daemon-example.log'  daemon = MyTestDaemon(pidfile=PIDFILE, stdout=LOG, stderr=LOG)  if len(sys.argv) != 2:    print('Usage: {} [start|stop]'.format(sys.argv[0]), file=sys.stderr)    raise SystemExit(1)  if 'start' == sys.argv[1]:    daemon.start()  elif 'stop' == sys.argv[1]:    daemon.stop()  elif 'restart' == sys.argv[1]:    daemon.restart()  else:    print('Unknown command {!r}'.format(sys.argv[1]), file=sys.stderr)    raise SystemExit(1)

[daemon] python test.py start                     23:45:42[daemon] cat /tmp/daemon-example.pid                 23:45:498532[daemon] ps -ef|grep 8532 | grep -v grep               23:46:07 502 8532   1  0 11:45下午 ??     0:00.00 python test.py start[daemon] tail -f /tmp/daemon-example.log               23:46:20Daemon started with pid 8532Daemon Alive! Fri Dec 2 23:45:49 2016Daemon Alive! Fri Dec 2 23:45:54 2016Daemon Alive! Fri Dec 2 23:45:59 2016Daemon Alive! Fri Dec 2 23:46:04 2016Daemon Alive! Fri Dec 2 23:46:09 2016Daemon Alive! Fri Dec 2 23:46:14 2016Daemon Alive! Fri Dec 2 23:46:19 2016Daemon Alive! Fri Dec 2 23:46:24 2016Daemon Alive! Fri Dec 2 23:46:29 2016Daemon Alive! Fri Dec 2 23:46:34 2016[daemon] python test.py stop                     23:46:36[daemon] ps -ef|grep 8532 | grep -v grep               23:46:43