兩者均需 import os
(1) os.system
# 僅僅在一個子終端運作系統指令，而不能擷取指令執行後的傳回資訊
system(command) -> exit_status
Execute the command (a string) in a subshell.
# 如果再指令行下執行，結果直接列印出來
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>>> os.system('ls')
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04101419778.CHM bash document media py-django video
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11.wmv books downloads Pictures python
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all-20061022 Desktop Examples project tools
(2) os.popen
# 該方法不但執行指令還傳回執行後的資訊對象
popen(command [, mode='r' [, bufsize]]) -> pipe
Open a pipe to/from a command returning a file object.
例如：
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>>>tmp = os.popen('ls *.py').readlines()
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>>>tmp
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Out[21]:
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['dump_db_pickle.py ',
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'dump_db_pickle_recs.py ',
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'dump_db_shelve.py ',
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'initdata.py ',
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'__init__.py ',
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'make_db_pickle.py ',
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'make_db_pickle_recs.py ',
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'make_db_shelve.py ',
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'peopleinteract_query.py ',
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'reader.py ',
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'testargv.py ',
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'teststreams.py ',
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'update_db_pickle.py ',
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'writer.py ']
好處在于：将傳回的結果賦于一變量，便于程式的處理。
(3) 使用子產品subprocess
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>>> import subprocess
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>>> subprocess.call (["cmd", "arg1", "arg2"],shell=True)
擷取傳回和輸出:
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import subprocess
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p = subprocess.Popen('ls', shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
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for line in p.stdout.readlines():
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print line,
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retval = p.wait()
(4) 使用子產品commands子產品
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>>> import commands
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>>> dir(commands)
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['__all__', '__builtins__', '__doc__', '__file__', '__name__', 'getoutput', 'getstatus','getstatusoutput', 'mk2arg', 'mkarg']
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>>> commands.getoutput("date")
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'Wed Jun 10 19:39:57 CST 2009'
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>>>
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>>> commands.getstatusoutput("date")
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(0, 'Wed Jun 10 19:40:41 CST 2009')
注意： 當執行指令的參數或者傳回中包含了中文文字，那麼建議使用subprocess，如果使用os.popen則會出現下面的錯誤:
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Traceback (most recent call last):
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File "./test1.py", line 56, in
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main()
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File "./test1.py", line 45, in main
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fax.sendFax()
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File "./mailfax/Fax.py", line 13, in sendFax
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os.popen(cmd)
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UnicodeEncodeError: 'ascii' codec can't encode characters in position 46-52: ordinal not inrange(128)