使用子进程来获取通过头-1输出的grep输出 [英] Using subprocess to get output of grep piped through head -1

问题描述

  grep -nsome phrase{some file路径} |头-1 
  

我想将这个输出传递给python。到目前为止，我尝试过的是：

pre $ subprocess.Popen（'grep -nsome phrase{some file path} | head -1'，shell = True，stdout = subprocess.PIPE）

大量的消息说：

 grep：writing output：Broken pipe
  

我对子流程模块不是很熟悉，我希望得到如何获得的建议此输出以及我目前做错的事情。

解决方案

该文档向您展示如何使用Popen替换外壳管道：

< $ {pre $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $'$'一些文件路径}']，stdout = PIPE）
p2 = Popen（['head'，'-1']，stdin = p1.stdout，stdout = PIPE）
p1.stdout.close ）＃允许p1接收一个SIGPIPE p2退出。
out，err = output = p2.communicate（）

The gist of what I'm trying to do is this:

grep -n "some phrase" {some file path} | head -1

I would like to pass the output of this into python. What I've tried so far is:

p = subprocess.Popen('grep -n "some phrase" {some file path} | head -1',shell=True,stdout=subprocess.PIPE)

I get back a lot of messages saying

"grep: writing output: Broken pipe"

I'm not very familiar with the subprocess module, I would like advice as to how to get this output, and what I am currently doing wrong.

解决方案

The docs show you how to replace shell piping using Popen:

from subprocess import PIPE, Popen


p1 = Popen(['grep', '-n', 'some phrase', '{some file path}'],stdout=PIPE)
p2 = Popen(['head', '-1'], stdin=p1.stdout, stdout=PIPE)
p1.stdout.close()  # Allow p1 to receive a SIGPIPE if p2 exits.
out,err = output = p2.communicate()

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