diff --git a/virtscreen/__main__.py b/virtscreen/__main__.py
index 58858df..5237741 100755
--- a/virtscreen/__main__.py
+++ b/virtscreen/__main__.py
@@ -79,40 +79,22 @@ def on_exit(self, signum=None, frame=None):
         signal.signal(sig, on_exit)
 
     args = vars(parser.parse_args())
-    # Enable logging
-    if args['log'] is None:
-        args['log'] = 'WARNING'
-    log_level = getattr(logging, args['log'].upper(), None)
-    if not isinstance(log_level, int):
-        error('Please choose a correct python logging level')
-        sys.exit(1)
-    # When logging level is INFO or lower, print logs in terminal
-    # Otherwise log to a file
-    log_to_file = True if log_level > logging.INFO else False
-    FORMAT = "[%(levelname)s:%(filename)s:%(lineno)s:%(funcName)s()] %(message)s"
-    logging.basicConfig(level=log_level, format=FORMAT,
-                        **({'filename': LOGGING_PATH} if log_to_file else {}))
-    if log_to_file:
-        logger = logging.getLogger()
-        handler = RotatingFileHandler(LOGGING_PATH, mode='a', maxBytes=1024*4, backupCount=1)
-        logger.addHandler(handler)
-    logging.info('logging enabled')
-    del args['log']
-    logging.info(f'{args}')
+    cli_args = ['auto', 'left', 'right', 'above', 'below', 'portrait', 'hidpi']
     # Start main
-    if any(args.values()):
+    if any((value and arg in cli_args) for arg, value in args.items()):
         main_cli(args)
     else:
-        main_gui()
+        main_gui(args)
     error('Program should not reach here.')
     sys.exit(1)
 
-def check_env(msg: Callable[[str], None]) -> None:
-    """Check environments before start"""
+def check_env(args: argparse.Namespace, msg: Callable[[str], None]) -> None:
+    """Check environments and arguments before start. This also enable logging"""
     if os.environ.get('XDG_SESSION_TYPE', '').lower() == 'wayland':
         msg("Currently Wayland is not supported")
         sys.exit(1)
-    if not HOME_PATH:
+    # Check ~/.config/virtscreen
+    if not HOME_PATH: # This is set in path.py
         msg("Cannot detect home directory.")
         sys.exit(1)
     if not os.path.exists(HOME_PATH):
@@ -121,9 +103,30 @@ def check_env(msg: Callable[[str], None]) -> None:
         except:
             msg("Cannot create ~/.config/virtscreen")
             sys.exit(1)
+    # Check x11vnc
     if not shutil.which('x11vnc'):
         msg("x11vnc is not installed.")
         sys.exit(1)
+    # Enable logging
+    if args['log'] is None:
+        args['log'] = 'WARNING'
+    log_level = getattr(logging, args['log'].upper(), None)
+    if not isinstance(log_level, int):
+        error('Please choose a correct python logging level')
+        sys.exit(1)
+    # When logging level is INFO or lower, print logs in terminal
+    # Otherwise log to a file
+    log_to_file = True if log_level > logging.INFO else False
+    FORMAT = "[%(levelname)s:%(filename)s:%(lineno)s:%(funcName)s()] %(message)s"
+    logging.basicConfig(level=log_level, format=FORMAT,
+                        **({'filename': LOGGING_PATH} if log_to_file else {}))
+    if log_to_file:
+        logger = logging.getLogger()
+        handler = RotatingFileHandler(LOGGING_PATH, mode='a', maxBytes=1024*4, backupCount=1)
+        logger.addHandler(handler)
+    logging.info('logging enabled')
+    del args['log']
+    logging.info(f'{args}')
     # Check if xrandr is correctly parsed.
     try:
         test = XRandR()
@@ -131,7 +134,7 @@ def check_env(msg: Callable[[str], None]) -> None:
         msg(str(e))
         sys.exit(1)
 
-def main_gui():
+def main_gui(args: argparse.Namespace):
     QApplication.setAttribute(Qt.AA_EnableHighDpiScaling)
     app = QApplication(sys.argv)
     loop = QEventLoop(app)
@@ -144,7 +147,7 @@ def dialog(message: str) -> None:
     if not QSystemTrayIcon.isSystemTrayAvailable():
         dialog("Cannot detect system tray on this system.")
         sys.exit(1)
-    check_env(dialog)
+    check_env(args, dialog)
 
     app.setApplicationName("VirtScreen")
     app.setWindowIcon(QIcon(ICON_PATH))
@@ -170,7 +173,7 @@ def dialog(message: str) -> None:
 def main_cli(args: argparse.Namespace):
     loop = asyncio.get_event_loop()
     # Check the environment
-    check_env(print)
+    check_env(args, print)
     if not os.path.exists(CONFIG_PATH):
         error("Configuration file does not exist.\n"
               "Configure a virtual screen using GUI first.")