Two methods for executing shell in python

This article mainly introduces two methods for executing shell in python. There are two ways to execute the SHELL program in Python. The first method is to use the commands package of Python, the second method is to use the subprocess package, both of which are existing Python built-in modules. For more information, see the following. 1. Use the built-in commands module of python to execute shell

Commands encapsulates Python OS. popen () and uses SHELL command strings as its parameters to return command result data and command execution status;

This command has been replaced by subprocess;

# Coding = UTF-8 ''' Created on August 1 @ author: crazyant.net ''' import commandsimport pprint def pai_exe (pai_string): print "will exe cmd, cmd:" + pai_string return commands. getstatusoutput (pai_string) if _ name __= = "_ main _": pprint. pprint (cmd_exe ("ls-la "))

II. run shell using python's latest subprocess module

Python has abandoned OS. system, OS. spawn *, OS. popen *, popen2. *, commands. * to execute commands in other languages. subprocesss is a recommended method;

Subprocess allows you to create many sub-processes. when you create a sub-process, it refers to the input, output, and error output pipelines of the sub-process and sub-process. after execution, you can obtain the output results and execution status.

# Coding = UTF-8 ''' Created on August 1 @ author: crazyant.net ''' import shleximport datetimeimport subprocessimport time def execute_command (optional string, cwd = None, timeout = None, shell = False ): "" executing a SHELL command encapsulates the Popen method of subprocess, and supports timeout judgment. it supports reading stdout and stderr parameters: cwd: changing the path when running the command. if it is set, the sub-process will directly change the current path to cwd timeout: time-out time, second, supports decimal, precision 0.1 second shell: whether to run Returns: return_code Raises: Exception through shell: execution timeout "if shell: repeated string_list = repeated string else: repeated string_list = shlex. split (distinct string) if timeout: end_time = datetime. datetime. now () + datetime. timedelta (seconds = timeout) # The media transcoding queue does not specify the standard output or error output. Therefore, the media transcoding queue is printed to the screen. sub = subprocess. popen (sort string_list, cwd = cwd, stdin = subprocess. PIPE, shell = shell, bufsize = 4096) # subprocess. poll () method: Check whether the sub-process is finished. if the sub-process is finished, set and return the code and place it in subprocess. while sub in the returncode variable. poll () is None: time. sleep (0.1) if timeout: if end_time <= datetime. datetime. now (): raise Exception ("Timeout: % s" % seconds string) return str (sub. returncode) if _ name __= = "_ main _": print execute_command ("ls ")

You can also specify stdin and stdout as a variable in Popen to directly receive the output variable value.

Summary

Sometimes SHELL execution in python is quite necessary. for example, different shell processes can be started using the Python thread mechanism. Currently, subprocess is the method officially recommended by Python and supports the most functions, we recommend that you use it.

Well, the above is all about this article. I hope this article will help you in your study or work. if you have any questions, please leave a message.

For more information about how to execute shell in python, see PHP!