Updated.

configure_netplan.py

@@ -30,12 +30,17 @@ def main():
 		if ethernets_block == None:
 			no_ethernets_block = True
 		else:
+			need_remove_interfaces = []
 			for interface in ethernets_block:
 				interface_block = ethernets_block[interface]
 				interface_addresses = interface_block.get('addresses')
 				if interface_addresses != None:
 					if len(interface_addresses) != 0:
 						addresses[interface] = interface_addresses
+				elif interface == '':
+					need_remove_interfaces.append(interface)
+			for interface in need_remove_interfaces:
+				del netplan_config_yaml['network']['ethernets'][interface]
 	if len(addresses) != 0:
 		print("You alreay configure some addresses for interfaces!")
 		for interface in addresses:
@@ -46,6 +51,12 @@ def main():
 		if ans.lower() != "y":
 			sys.exit()
 	default_interfaces = list(set(subprocess.Popen("ip -o -4 route show to default | awk '{print $5}'", shell=True, stdout=subprocess.PIPE).stdout.read().decode().strip().split("\n")))
+	if '' in default_interfaces:
+		default_interfaces.remove('')
+	if len(default_interfaces) == 0:
+		default_interfaces.extend(subprocess.Popen("ls /sys/class/net/|xargs", shell=True, stdout=subprocess.PIPE).stdout.read().decode().strip().split(" "))
+		if 'lo' in default_interfaces:
+			default_interfaces.remove('lo')
 	if len(default_interfaces) == 0:
 		if len(args) > 2:
 			default_interfaces = args[2]
@@ -74,7 +85,15 @@ def main():
 					print("Invalid ipaddress!")
 					new_addr = ""
 			addresses[interface] = [new_addr + '/24']
+			new_gateway4 = input(f"New gateway4 for interface {interface}: (can leave blank by default 254)")
 			gateway4[interface] = re.sub('[\\d]+$', '254', new_addr)
+			if new_gateway4 != "":
+				try:
+					ipaddress.IPv4Address(new_gateway4)
+					gateway4[interface] = new_gateway4
+				except:
+					print("Invalid gateway4 ipaddress!")
+					print(f"Change to default: {gateway4[interface]}")
 			change_flag = True
 		else:
 			change_flag = True