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\’)
min=disabled,24,11,8,7
max=40
passphrase=3
match=4
similar=deny
random=47
enforce=everyone
retry=3
Out[6]: 0

2 os.popen()

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,
…

3 如何同时返回结果和运行状态，commands模块:

#String form: 
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\’)
In [25]: status
Out[25]: 0
In [26]: len(output)
Out[26]: 3859

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)
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。