PR: Add command line option to connect to an existing kernel at startup (IPython console)

spyder/app/cli_options.py

@@ -157,6 +157,13 @@ def get_options(argv=None):
         default=None,
         help="Choose a configuration directory to use for Spyder."
     )
+    parser.add_argument(
+        '--connect-to-kernel',
+        type=str,
+        dest="connection_file",
+        default=None,
+        help="Start Spyder and connect to an existing ipython kernel."
+    )
 
     parser.add_argument('files', nargs='*')
     options = parser.parse_args(argv)

spyder/plugins/ipythonconsole/plugin.py

@@ -559,7 +559,12 @@ def on_close(self, cancelable=False):
         return self.get_widget().close_all_clients()
 
     def on_mainwindow_visible(self):
-        self.create_new_client(give_focus=False)
+        cli_options = self.get_command_line_options()
+        connection_file = cli_options.connection_file
+        if connection_file is not None:
+            self.create_client_for_kernel(connection_file)
+        else:
+            self.create_new_client(give_focus=False)
 
     # ---- Private methods
     # -------------------------------------------------------------------------