The timeout argument is passed to . If the timeout expires, the child process will be killed and waited for. The  exception will be re-raised after the child process has terminated.

The input argument is passed to  and thus to the subprocess’s stdin. If used it must be a byte sequence, or a string if universal_newlines=True. When used, the internal  object is automatically created withstdin=PIPE, and the stdin argument may not be used as well.

If check is True, and the process exits with a non-zero exit code, a  exception will be raised. Attributes of that exception hold the arguments, the exit code, and stdout and stderr if they were captured.

常用subprocess方法示例

#执行命令，返回命令执行状态 ， 0 or 非0
>>> retcode = subprocess.call(["ls", "-l"])

#执行命令，如果命令结果为0，就正常返回，否则抛异常
>>> subprocess.check_call(["ls", "-l"])
0

#接收字符串格式命令，返回元组形式，第1个元素是执行状态，第2个是命令结果
>>> subprocess.getstatusoutput('ls /bin/ls')
(0, '/bin/ls')

#接收字符串格式命令，并返回结果
>>> subprocess.getoutput('ls /bin/ls')
'/bin/ls'

#执行命令，并返回结果，注意是返回结果，不是打印，下例结果返回给res
>>> res=subprocess.check_output(['ls','-l'])
>>> res
b'total 0\ndrwxr-xr-x 12 alex staff 408 Nov 2 11:05 OldBoyCRM\n'

#上面那些方法，底层都是封装的subprocess.Popen
poll()
Check if child process has terminated. Returns returncode

wait()
Wait for child process to terminate. Returns returncode attribute.

terminate() 杀掉所启动进程
communicate() 等待任务结束

stdin 标准输入

stdout 标准输出

stderr 标准错误

pid
The process ID of the child process.

#例子
>>> p = subprocess.Popen("df -h|grep disk",stdin=subprocess.PIPE,stdout=subprocess.PIPE,shell=True)
>>> p.stdout.read()
b'/dev/disk1 465Gi 64Gi 400Gi 14% 16901472 104938142 14% /\n'

 

 

 

>>> subprocess.run(["ls", "-l"]) # doesn't capture output CompletedProcess(args=['ls', '-l'], returncode=0) >>> subprocess.run("exit 1", shell=True, check=True) Traceback (most recent call last): ... subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1 >>> subprocess.run(["ls", "-l", "/dev/null"], stdout=subprocess.PIPE) CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0, stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n')

 

调用subprocess.run(...)是推荐的常用方法，在大多数情况下能满足需求，但如果你可能需要进行一些复杂的与系统的交互的话，你还可以用subprocess.Popen(),语法如下：

p = subprocess.Popen("find / -size +1000000 -exec ls -shl {} \;",shell=True,stdout=subprocess.PIPE) print(p.stdout.read())

可用参数：

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

需要交互的命令示例

import subprocess obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) obj.stdin.write('print 1 \n ') obj.stdin.write('print 2 \n ') obj.stdin.write('print 3 \n ') obj.stdin.write('print 4 \n ') out_error_list = obj.communicate(timeout=10) print out_error_list

subprocess实现sudo 自动输入密码

import subprocess def mypass(): mypass = '123' #or get the password from anywhere return mypass echo = subprocess.Popen(['echo',mypass()], stdout=subprocess.PIPE, ) sudo = subprocess.Popen(['sudo','-S','iptables','-L'], stdin=echo.stdout, stdout=subprocess.PIPE, ) end_of_pipe = sudo.stdout print "Password ok \n Iptables Chains %s" % end_of_pipe.read()

　　

　　

logging模块　　

很多程序都有记录日志的需求，并且日志中包含的信息即有正常的程序访问日志，还可能有错误、警告等信息输出，python的logging模块提供了标准的日志接口，你可以通过它存储各种格式的日志，logging的日志可以分为 , , ,  and  5个级别，下面我们看一下怎么用。

最简单用法

import logging logging.warning("user [alex] attempted wrong password more than 3 times") logging.critical("server is down") #输出 WARNING:root:user [alex] attempted wrong password more than 3 times CRITICAL:root:server is down

看一下这几个日志级别分别代表什么意思

LevelWhen it’s used

DEBUG Detailed information, typically of interest only when diagnosing problems.

INFO Confirmation that things are working as expected.

WARNING An indication that something unexpected happened, or indicative of some problem in the near future (e.g. ‘disk space low’). The software is still working as expected.

ERROR Due to a more serious problem, the software has not been able to perform some function.

CRITICAL A serious error, indicating that the program itself may be unable to continue running.

　　

如果想把日志写到文件里，也很简单