问题
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.
回答1:
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()
回答2:
Let shell do it for you (lazy workaround):
import subprocess
p = subprocess.Popen(['-c', 'grep -n "some phrase" {some file path} | head -1'], shell=True, stdout=subprocess.PIPE)
out, err = p.communicate()
print out, err
来源：https://stackoverflow.com/questions/28154437/using-subprocess-to-get-output-of-grep-piped-through-head-1