日常整理python执行系统命令的常见方法(全)
具体内容如下: 1 os.system 例如 ipython中运行如下命令,返回运行状态status os.system('cat /etc/passwdqc.conf') 2 os.popen() popen(command [,mode='r' [,bufsize]]) -> pipe 运行返回结果 In [20]: output = os.popen('cat /proc/cpuinfo') 3 如何同时返回结果和运行状态,commands模块: #String form: <module 'commands' from '/usr/lib64/python2.7/commands.pyc'> File: /usr/lib64/python2.7/commands.py Docstring: Execute shell commands via os.popen() and return status,output. Interface summary: import commands outtext = commands.getoutput(cmd) (exitstatus,outtext) = commands.getstatusoutput(cmd) outtext = commands.getstatus(file) # returns output of "ls -ld file" A trailing newline is removed from the output string. Encapsulates the basic operation: pipe = os.popen('{ ' + cmd + '; } 2>&1','r') text = pipe.read() sts = pipe.close() commands示例如下: In [24]: (status,output) = commands.getstatusoutput('cat /proc/cpuinfo') 4 使用模块subprocess ipython 中运行"?subprocess"可以发现subprocess是python用来替换os.popen()等管道操作命令的新模块 A more real-world example would look like this: try: retcode = call("mycmd" + " myarg",shell=True) if retcode < 0: print >>sys.stderr,"Child was terminated by signal",-retcode else: print >>sys.stderr,"Child returned",retcode except OSError,e: print >>sys.stderr,"Execution failed:",e 相对于上面几种方式,subprocess便于控制和监控进程运行结果,subprocess提供多种函数便于应对父进程对子进程不同要求: 4.1.1 subprocess.call() 父进程父进程等待子进程完成,返回exit code 4.1.2 subprocess.check_call() 父进程等待子进程完成,返回0,如果returncode不为0,则举出错误subprocess.CalledProcessError,该对象包含有returncode属性,可用try...except...来检查 4.1.3 subprocess.check_output() 父进程等待子进程完成 返回子进程向标准输出的输出结果 检查退出信息,如果returncode不为0,则举出错误subprocess.CalledProcessError,该对象包含有returncode属性和output属性,output属性为标准输出的输出结果,可用try...except...来检查 例如: In [32]: out = subprocess.call("ls -l",shell=True) 4.2.1 上面三个函数都是源于Popen()函数的wapper(封装),如果需要更加个性化应用,那么就需要使用popen()函数 Popen对象创建后,主程序不会自动等待子进程完成。我们必须调用对象的wait()方法,父进程才会等待 (也就是阻塞block) [wenwt@localhost syntax]$ rm subprocess.pyc [wenwt@localhost syntax]$ python process.py parent process [wenwt@localhost syntax]$ PING www.google.com (173.194.219.99) 56(84) bytes of data. ^C [wenwt@localhost syntax]$ --- www.google.com ping statistics --- 5 packets transmitted,0 received,100% packet loss,time 3999ms 加上wait方法: [wenwt@localhost syntax]$ python process.py PING www.google.com (173.194.219.103) 56(84) bytes of data. --- www.google.com ping statistics --- 5 packets transmitted,time 3999ms parent process 以上内容就是本文的全部叙述,希望大家喜欢。 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |