Get the systems ethernet BSD device

getPlatformPortName.py

#!/usr/bin/python
import re
import commands
import plistlib
from subprocess import Popen, PIPE, STDOUT

networksetup    = '/usr/sbin/networksetup'
sysctl          = '/usr/sbin/sysctl'

# Hardware Test for MacbookAir,*
def getPlatformPortName():
  # Hardware test for Air
  airTest = re.compile(".*(a|A)ir.*")
  hwmodel = commands.getoutput(sysctl + " hw.model").split(' ')
  if osVersion['minor'] >= LION:
    # Updating this for retina displays and beyond?
    arguments = [networksetup,'-listallhardwareports']
    execute = Popen(arguments, stdout=PIPE)
    out, err = execute.communicate()
    retina_regex  = re.search(".*(Wi-Fi|AirPort).*\nDevice: (en\d+)*",out)
    bsd_port      = retina_regex.group(2)
    return bsd_port
  else:
    if airTest.match(hwmodel[-1]):
      return 'en0'
    else:
      return 'en1'

def getSystemVersion():
  # Our Operating System Constants
  global LEOP,SNOW,LION,MLION,MAVRK
  LEOP = 5
  SNOW = 6
  LION = 7
  MLION = 8
  MAVRK = 9
  systemVersionPath = '/System/Library/CoreServices/SystemVersion.plist'
  try:
    systemVersion = plistlib.Plist.fromFile(systemVersionPath)
  except:
    print 'Unable to parse file at path: %s' % systemVersion
    sys.exit(1)
  ProductVersion = systemVersion['ProductVersion'].split('.')
  returnDict = {}
  returnDict['major'] = int(ProductVersion[0])
  returnDict['minor'] = int(ProductVersion[1])
  returnDict['bugfx'] = int(ProductVersion[2])
  return returnDict

# Get OS Version
global osVersion
osVersion = getSystemVersion()
print getPlatformPortName()