转 Python执行系统命令的方法

时间：2016-08-14 17:45:34 阅读：231 评论：0 收藏：0 [点我收藏+]

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Python执行系统命令的方法

http://www.linux-field.com/?p=15

Python中执行系统命令常见方法有两种：

两者均需 import os

(1) os.system

# 仅仅在一个子终端运行系统命令，而不能获取命令执行后的返回信息

system(command) -> exit_status
Execute the command (a string) in a subshell.

# 如果再命令行下执行，结果直接打印出来

1 >>> os.system(‘ls‘)
2 04101419778.CHM   bash      document    media      py-django   video
3 11.wmv            books     downloads   Pictures  python
4 all-20061022      Desktop   Examples    project    tools

(2) os.popen

# 该方法不但执行命令还返回执行后的信息对象

popen(command [, mode=‘r‘ [, bufsize]]) -> pipe
Open a pipe to/from a command returning a file object.

例如：

 1 >>>tmp = os.popen(‘ls *.py‘).readlines()
 2 >>>tmp
 3 Out[21]:
 4 [‘dump_db_pickle.py ‘,
 5 ‘dump_db_pickle_recs.py ‘,
 6 ‘dump_db_shelve.py ‘,
 7 ‘initdata.py ‘,
 8 ‘__init__.py ‘,
 9 ‘make_db_pickle.py ‘,
10 ‘make_db_pickle_recs.py ‘,
11 ‘make_db_shelve.py ‘,
12 ‘peopleinteract_query.py ‘,
13 ‘reader.py ‘,
14 ‘testargv.py ‘,
15 ‘teststreams.py ‘,
16 ‘update_db_pickle.py ‘,
17 ‘writer.py ‘]

好处在于：将返回的结果赋于一变量，便于程序的处理。

(3) 使用模块subprocess

1 >>> import subprocess
2 >>> subprocess.call (["cmd", "arg1", "arg2"],shell=True)

获取返回和输出:

1 import subprocess
2 p = subprocess.Popen(‘ls‘, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
3 for line in p.stdout.readlines():
4     print line,
5 retval = p.wait()

(4) 使用模块commands模块

1 >>> import commands
2 >>> dir(commands)
3 [‘__all__‘, ‘__builtins__‘, ‘__doc__‘, ‘__file__‘, ‘__name__‘, ‘getoutput‘, ‘getstatus‘,‘getstatusoutput‘, ‘mk2arg‘, ‘mkarg‘]
4 >>> commands.getoutput("date")
5 ‘Wed Jun 10 19:39:57 CST 2009‘
6 >>>
7 >>> commands.getstatusoutput("date")
8 (0, ‘Wed Jun 10 19:40:41 CST 2009‘)

注意：当执行命令的参数或者返回中包含了中文文字，那么建议使用subprocess，如果使用os.popen则会出现下面的错误:

1 Traceback (most recent call last):
2   File "./test1.py", line 56, in <module>
3     main()
4   File "./test1.py", line 45, in main
5     fax.sendFax()
6   File "./mailfax/Fax.py", line 13, in sendFax
7     os.popen(cmd)
8 UnicodeEncodeError: ‘ascii‘ codec can‘t encode characters in position 46-52: ordinal not inrange(128)