python中使用subprocess批量执行linux下命令

PpikachuP 2019-06-27

可以执行shell命令的相关模块和函数有:

  • os.system
  • os.spawn
  • os.popen --废弃
  • popen --废弃
  • commands --废弃,3.x中被移除

以上执行shell命令的相关的模块和函数的功能均在 subprocess 模块中实现,并提供了更丰富的功能。

subprocess

call

执行命令,返回状态码

>>> import subprocess
>>> ret = subprocess.call(["ls", "-l"], shell=False)
total 4684
-rw-r--r-- 1 root root     454 May  5 12:20 aa.py
-rw-r--r-- 1 root root       0 May  8 16:51 aa.txt
-rw-r--r-- 1 root root 4783286 Apr 11 16:39 DockerToolbox.exe
-rw-r--r-- 1 root root     422 May  5 12:20 ip_info.txt
-rw-r--r-- 1 root root     718 Apr 19 10:52 my.cnf
>>> ret = subprocess.call("ls -l", shell=True)
total 4684
-rw-r--r-- 1 root root     454 May  5 12:20 aa.py
-rw-r--r-- 1 root root       0 May  8 16:51 aa.txt
-rw-r--r-- 1 root root 4783286 Apr 11 16:39 DockerToolbox.exe
-rw-r--r-- 1 root root     422 May  5 12:20 ip_info.txt
-rw-r--r-- 1 root root     718 Apr 19 10:52 my.cnf
>>> print(ret)
0

check_call

执行命令,如果执行状态码是 0 ,则返回0,否则抛异常

>>> subprocess.check_call(["ls", "-l"])
total 4684
-rw-r--r-- 1 root root     454 May  5 12:20 aa.py
-rw-r--r-- 1 root root       0 May  8 16:51 aa.txt
-rw-r--r-- 1 root root 4783286 Apr 11 16:39 DockerToolbox.exe
-rw-r--r-- 1 root root     422 May  5 12:20 ip_info.txt
-rw-r--r-- 1 root root     718 Apr 19 10:52 my.cnf
0
>>> subprocess.check_call("exit 1", shell=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/python3.5/lib/python3.5/subprocess.py", line 581, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

check_output

执行命令,如果状态码是 0 ,则返回执行结果,否则抛异常

>>> subprocess.check_output(["echo", "Hello World!"])
b'Hello World!\n'
>>> subprocess.check_output("exit 1", shell=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/python3.5/lib/python3.5/subprocess.py", line 626, in check_output
    **kwargs).stdout
  File "/usr/local/python3.5/lib/python3.5/subprocess.py", line 708, in run
    output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

subprocess.Popen(...)

用于执行复杂的系统命令
参数:

args:shell命令,可以是字符串或者序列类型(如:list,元组)
bufsize:指定缓冲。0 无缓冲,1 行缓冲,其他 缓冲区大小,负值 系统缓冲
stdin, stdout, stderr:分别表示程序的标准输入、输出、错误句柄
preexec_fn:只在Unix平台下有效,用于指定一个可执行对象(callable object),它将在子进程运行之前被调用
close_sfs:在windows平台下,如果close_fds被设置为True,则新创建的子进程将不会继承父进程的输入、输出、错误管道。
所以不能将close_fds设置为True同时重定向子进程的标准输入、输出与错误(stdin, stdout, stderr)。
shell:同上
cwd:用于设置子进程的当前目录
env:用于指定子进程的环境变量。如果env = None,子进程的环境变量将从父进程中继承。
universal_newlines:不同系统的换行符不同,True -> 同意使用 n
startupinfo与createionflags只在windows下有效
将被传递给底层的CreateProcess()函数,用于设置子进程的一些属性,如:主窗口的外观,进程的优先级等等

执行普通命令

>>> import subprocess
>>> ret1 = subprocess.Popen(["mkdir","t1"])
>>> ret2 = subprocess.Popen("mkdir t2", shell=True)
>>> print(ret1)
<subprocess.Popen object at 0x7f4d7609dd30>
>>> print(ret2)
<subprocess.Popen object at 0x7f4d7609dc18>

终端输入的命令分为两种:

  • 输入即可得到输出,如:ifconfig
  • 输入进行某环境,依赖再输入,如:python
>>> import subprocess
>>> obj = subprocess.Popen("mkdir t3", shell=True, cwd='/tmp/',)
>>> import subprocess
>>> obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
>>> obj.stdin.write("print(1)\n")
9
>>> obj.stdin.write("print(2)")
8
>>> obj.stdin.close()
>>> cmd_out = obj.stdout.read()
>>> obj.stdout.close()
>>> cmd_error = obj.stderr.read()
>>> obj.stderr.close()
>>> print(cmd_out)
1
2
>>> print(cmd_error)
>>> import subprocess
>>> 
>>> obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
>>> obj.stdin.write("print(1)\n")
9
>>> obj.stdin.write("print(2)")
8
>>> 
>>> out_error_list = obj.communicate()
>>> print(out_error_list)
('1\n2\n', '')
>>> obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
>>> out_error_list = obj.communicate('print("hello")')
>>> print(out_error_list)
('hello\n', '')

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