How to get the IP address of a Linux system

之前在 Windows/Mac OS 取得 ip address 透過

import socket
print socket.gethostbyname(socket.gethostname())

都沒問題。但在  Linux 裡出問題了。

print socket.gethostbyname_ex(socket.gethostname())

完全沒取到 ip,

替代解法是：

from subprocess import check_output
ipAddr = check_output(["hostname", "-I"])

但這段 code 在  Mac OS 上跑會出錯：

ipAddr = check_output(["hostname", "-I"])
 File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 573, in check_output
 raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['hostname', '-I']' returned non-zero exit status 1