FNAME = "ifconfig_u18.txt"  # Ubuntu 18.04
  # FNAME = "ifconfig.txt"  # Ubuntu 16.04
  ADAPTERS = dict()
  SEARCHSTR = "ether"  # Ubuntu 18.04
  # SEARCHSTR = "HWaddr"  # Ubuntu 16.04
  MACADDRLEN = 17  # 6 Byte = 6 * 2 = 12 + 5 = 17
  macaddr = ""
  
  with open(FNAME) as fid:
      for linenumber, line in enumerate(fid):
          if (line and ("lo" not in line) and ("tun" not in line)):
              if line[0] != " ":
                  adapter = line.split(" ")[0].replace(":", "")
              if SEARCHSTR in line:
                  startidx = line.find(SEARCHSTR) + len(SEARCHSTR) + 1
                  macaddr = line[startidx : startidx + MACADDRLEN]
              if adapter.strip() and macaddr:
                  ADAPTERS[adapter] = macaddr
  
  
  FNAME_BASE = FNAME[:FNAME.rfind(".txt")]
  FNAME_OUT = FNAME_BASE + "_adapters.txt"
  FNAME_OUT2 = FNAME_BASE + "_adapters_changed.txt"
  
  with open(FNAME_OUT, "w") as fid:
      for linenumber, (adapter, mac) in enumerate(ADAPTERS.items()):
          print(linenumber, adapter, mac)
          fid.write("Adapter: " +  adapter + ", MAC: " + mac + "\n")
  
  BASEMAC = "01:23:45:ff:00:"
  with open(FNAME_OUT2, "w") as fid:
      for i, (adapter, mac) in enumerate(ADAPTERS.items()):
          mac_changed = BASEMAC + "%02x" %(i+1)
          mac_changed = BASEMAC + "{0:02x}".format((i+1))
          fid.write("Adapter: " +  adapter + ", MAC: " + mac_changed + "\n")