Allow overriding individual configuration options on the command line

kitty/config.py

@@ -242,7 +242,7 @@ def merge_configs(ans, vals):
     return ans
 
 
-def load_config(*paths) -> Options:
+def load_config(*paths, overrides=None) -> Options:
     ans = defaults._asdict()
     for path in paths:
         if not path:
@@ -254,6 +254,9 @@ def load_config(*paths) -> Options:
         with f:
             vals = parse_config(f)
             ans = merge_configs(ans, vals)
+    if overrides is not None:
+        vals = parse_config(overrides)
+        ans = merge_configs(ans, vals)
     return Options(**ans)
 
 

kitty/main.py

@@ -54,6 +54,15 @@ def option_parser():
             ' config files in sequence, which are merged. Default: {}'
         ).format(defconf)
     )
+    a(
+        '--override',
+        '-o',
+        action='append',
+        help=_(
+            'Override individual configuration options, can be specified'
+            ' multiple times. Syntax: name=value. For example: {}'
+        ).format('-o font_size=20')
+    )
     a(
         '--cmd',
         '-c',
@@ -213,7 +222,8 @@ def main():
         main(args.replay_commands)
         return
     config = args.config or (defconf, )
-    opts = load_config(*config)
+    overrides = (a.replace('=', ' ', 1) for a in args.override)
+    opts = load_config(*config, overrides=overrides)
     change_wcwidth(not opts.use_system_wcwidth)
     glfw_set_error_callback(on_glfw_error)
     enable_automatic_opengl_error_checking(False)