源码网商城,靠谱的源码在线交易网站 我的订单 购物车 帮助

源码网商城

日常整理python执行系统命令的常见方法(全)

  • 时间:2022-01-13 13:07 编辑: 来源: 阅读:
  • 扫一扫,手机访问
摘要:日常整理python执行系统命令的常见方法(全)
具体内容如下: [b]1 os.system[/b] 例如 ipython中运行如下命令,返回运行状态status os.system('cat /etc/passwdqc.conf') min=disabled,24,11,8,7 max=40 passphrase=3 match=4 similar=deny random=47 enforce=everyone retry=3 Out[6]: 0 [b]2 os.popen()[/b] popen(command [, mode='r' [, bufsize]]) -> pipe Open a pipe to/from a command returning a file object. 运行返回结果 In [20]: output = os.popen('cat /proc/cpuinfo') In [21]: lineLen = [] In [22]: for line in output.readlines():     lineLen.append(len(line))    ....:     In [23]: line line     lineLen  In [23]: lineLen Out[23]: [14,  25, ... [b]3 如何同时返回结果和运行状态,commands模块:[/b]
#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()
[b]commands示例如下:[/b] In [24]: (status, output) = commands.getstatusoutput('cat /proc/cpuinfo') In [25]: status Out[25]: 0 In [26]: len(output) Out[26]: 3859 [b]4 使用模块subprocess[/b] 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) total 42244 -rw-rw-r--.  1 *** ***     366 May 26 09:10 ChangeLog 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, 0 received, 100% packet loss, time 3999ms
parent process
以上内容就是本文的全部叙述,希望大家喜欢。
  • 全部评论(0)
联系客服
客服电话:
400-000-3129
微信版

扫一扫进微信版
返回顶部