如何从 Python 中的命令 output 解析和查找内容

Question

I would like to find only the IP address from the command output of ifconfig :

import os

ip = os.system("ifconfig eth0")

How do I then find 192.168.1.10 from the output and print that to standard output?

Answer 1

ip=os.system("ifconfig eth0|grep -w 'inet'|awk '{print $2}'")

This solution is with pure shell commands. Grep searches for the word inet and prints the line, awk then filters for the second word and this is the IP

Answer 2

or

import subprocess

import re

ip=subprocess.Popen(['ifconfig', 'eth0'], stdout=subprocess.PIPE).communicate()[0]

oip=re.search(r"[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}", str(ip))

print(oip.group())

Here regular expressions are applied to the ifconfig command. The first occurrence of a string is searched for, which has 4 numbers, each number maximum 3 digits long, separated by a dot.