Python中执行系统命令

0x00 使用模块

在python执行系统命令一般可以通过3个模块来实现,这三个模块是:os、commands、subprocess

0x01 os模块执行系统命令

一般用os模块的system函数来执行一些简单的命令

>>> import os
>>> os.system("pwd")
/Users/reber
0

0x02 commands模块执行系统命令

commands这个模块在python3中被移除了

>>> import commands
>>> commands.getoutput("pwd")
'/Users/reber'
>>> commands.getstatusoutput("pwd")
(0, '/Users/reber') #返回状态码以及结果

0x03 subprocess模块执行系统命令

  • task.py代码
def aaa():
    s = 0
    for x in range(3):
        time.sleep(1)
        s += x
    return s

print(aaa())
  • call函数执行命令(会阻塞到任务完成)
    函数原型:subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False)
>>> from subprocess import call
>>> call(["ls","-l"]) #传入一个list
total 16
-rw-r--r--   1 reber  staff    80  8 16 16:19 README.md
drwxr-xr-x@  3 reber  staff   102  3 14  2017 archetypes
-rwxr-xr-x@  1 reber  staff  1403 12 13 17:43 config.toml
drwxr-xr-x@  4 reber  staff   136 12  9 23:02 content
drwxr-xr-x@  7 reber  staff   238  4 26  2017 layouts
drwxr-xr-x@ 19 reber  staff   646 10 11 12:33 public
drwxr-xr-x@  7 reber  staff   238 10 11 12:33 static
0
>>> call("ls -l",shell=True) #shell设置为True时可以传入一个字符串
total 16
-rw-r--r--   1 reber  staff    80  8 16 16:19 README.md
drwxr-xr-x@  3 reber  staff   102  3 14  2017 archetypes
-rwxr-xr-x@  1 reber  staff  1403 12 13 17:43 config.toml
drwxr-xr-x@  4 reber  staff   136 12  9 23:02 content
drwxr-xr-x@  7 reber  staff   238  4 26  2017 layouts
drwxr-xr-x@ 19 reber  staff   646 10 11 12:33 public
drwxr-xr-x@  7 reber  staff   238 10 11 12:33 static
0
  • Popen函数进行进程交互(非阻塞)
>>> from subprocess import Popen,PIPE,STDOUT
>>> h = Popen("ls dsfj",stdout=PIPE,stderr=STDOUT,shell=True)
>>> h.stdout.read() #从数据流中读出数据,如果数据流过大且不读数据的话可能会死锁
'ls: dsfj: No such file or directory\n'
>>> h.stderr.read() #使用的是STDOUT,将错误通过标准输出流输出,没有read方法
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'read'


>>> h = Popen("ls dsfj",stdout=PIPE,stderr=PIPE,shell=True)
>>> h.stdout.read()
''
>>> h.stderr.read()
'ls: dsfj: No such file or directory\n'


>>> cmd = "python /Users/reber/Desktop/task.py"
>>> h = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True)
>>> stdoutput = h.stdout.read() #stdoutput,erroutput = h.communicate()
>>> erroutput = h.stdout.read()
>>> stdoutput,erroutput
('3\n', '')
>>> h.pid,h.poll() #子进程id,执行结果状态码(0代表成功)
(49787, 0)


>>> f = open('a.txt','a+')
>>> h = Popen("ls -l", stdout=f, stderr=PIPE, shell=True) #写入文件
>>> h = Popen("ifconfig", shell=True, stdout=f, stderr=PIPE)
>>> f.close()
  • 在python3中subprocess实现了commands的getstatusoutput方法
$ py3
(py3env) [16:28 reber@wyb in ~/wyb0.com git:(master) ✗]
$ python
Python 3.6.3 (default, Oct  4 2017, 06:09:15)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.37)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from subprocess import getstatusoutput
>>> cmd = "python /Users/reber/Desktop/task.py"
>>> getstatusoutput(cmd)
(0, '3')
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