subprocess.run与subprocess.pepon

subprocess模块在Python中用于执行外部命令，run()和Popen()都是其中的重要函数。
subprocess.run()[^1] 是一个便捷的方法，它简化了创建子进程并获取其输出的过程。它会直接执行指定的命令，返回一个CompletedProcess对象，包含了退出状态、标准输出和错误输出：
import subprocess

# 使用run()
cmd_result = subprocess.run(['ls', '-l'])
print(cmd_result.stdout.decode()) # 打印目录内容

相比之下，Popen() 提供了更多的控制选项，比如更灵活的命令参数传递（通过args参数），以及能够独立管理子进程的生命周期（如communicate()方法用于接收输出）。这里是一个使用Popen()的例子：
# 使用Popen()
proc = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)
output, error = proc.communicate()
print(output.decode()) # 同样打印目录内容

相关问题

subprocess.Popen subprocess.run

subprocess.Popen and subprocess.run are both modules in Python's subprocess module that are used for running external commands. Here's a brief explanation of each:

subprocess.Popen: This function is used to create a new process and execute a command within it. It provides more flexibility and control over the execution process. Popen returns a Popen object, which allows you to interact with the running process, such as reading its output or terminating it.

Example usage:
import subprocess

# Run a command and get its output
result = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)
output = result.communicate()
print(output.decode('utf-8'))

subprocess.run: This function is a higher-level convenience function introduced in Python 3.5. It is used to run a command and wait for it to complete. It returns a CompletedProcess object that provides information about the completed process, such as return code and output.

Example usage:
import subprocess

# Run a command and get its output
result = subprocess.run(['ls', '-l'], capture_output=True, text=True)
print(result.stdout)

Both functions can be used to execute external commands, but the choice between them depends on your requirements. Popen offers more flexibility, while run provides a simpler and more straightforward way to execute commands.

subprocess.run(shell, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)

subprocess.run() 是 Python 中一个用于执行外部命令的函数。它可以接受一个字符串形式的 shell 命令作为参数，并返回一个 CompletedProcess 对象，其中包含了命令执行的结果等信息。
在这个函数中，stdout=subprocess.DEVNULL 和 stderr=subprocess.DEVNULL 都是用来将标准输出和标准错误输出重定向到空设备上，从而避免在命令执行过程中在终端或日志中看到这些输出。这样做的好处是可以让命令在后台默默执行，提高程序的执行效率。