Simplify cli.py and fix Detect train Usage (#83)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/cli.py

@@ -13,9 +13,9 @@ from .utils import LOGGER, colorstr
 @hydra.main(version_base=None, config_path="utils/configs", config_name="default")
 def cli(cfg):
     LOGGER.info(f"{colorstr(f'Ultralytics YOLO v{ultralytics.__version__}')}")
+    task, mode = cfg.task.lower(), cfg.mode.lower()
 
-    module_file = None
-    if cfg.task.lower() == "init":  # special case
+    if task == "init":  # special case
         shutil.copy2(DEFAULT_CONFIG, os.getcwd())
         LOGGER.info(f"""
         {colorstr("YOLO :")} configuration saved to {os.getcwd()}/{DEFAULT_CONFIG.name}.
@@ -23,25 +23,21 @@ def cli(cfg):
         yolo task='task' mode='mode' --config-name config_file.yaml
                     """)
         return
-    elif cfg.task.lower() == "detect":
+    elif task == "detect":
         module_file = yolo.detect
-    elif cfg.task.lower() == "segment":
+    elif task == "segment":
         module_file = yolo.segment
-    elif cfg.task.lower() == "classify":
+    elif task == "classify":
         module_file = yolo.classify
+    else:
+        raise SyntaxError("task not recognized. Choices are `'detect', 'segment', 'classify'`")
 
-    if not module_file:
-        raise Exception("task not recognized. Choices are `'detect', 'segment', 'classify'`")
-
-    module_function = None
-
-    if cfg.mode.lower() == "train":
+    if mode == "train":
         module_function = module_file.train
-    elif cfg.mode.lower() == "val":
+    elif mode == "val":
         module_function = module_file.val
-    elif cfg.mode.lower() == "predict":
+    elif mode == "predict":
         module_function = module_file.predict
-
-    if not module_function:
-        raise Exception("mode not recognized. Choices are `'train', 'val', 'predict'`")
+    else:
+        raise SyntaxError("mode not recognized. Choices are `'train', 'val', 'predict'`")
     module_function(cfg)

ultralytics/yolo/v8/detect/train.py

@@ -223,9 +223,9 @@ def train(cfg):
 if __name__ == "__main__":
     """
     CLI usage:
-    python ultralytics/yolo/v8/segment/train.py cfg=yolov5n-seg.yaml data=coco128-segments epochs=100 img_size=640
+    python ultralytics/yolo/v8/detect/train.py model=yolov5n.yaml data=coco128 epochs=100 img_size=640
 
     TODO:
-    Direct cli support, i.e, yolov8 classify_train args.epochs 10
+    yolo task=detect mode=train model=yolov5n.yaml data=coco128.yaml epochs=100
     """
     train()

ultralytics/yolo/v8/segment/train.py

@@ -243,7 +243,7 @@ def train(cfg):
 if __name__ == "__main__":
     """
     CLI usage:
-    python ultralytics/yolo/v8/segment/train.py cfg=yolov5n-seg.yaml data=coco128-segments epochs=100 img_size=640
+    python ultralytics/yolo/v8/segment/train.py model=yolov5n-seg.yaml data=coco128-segments epochs=100 img_size=640
 
     TODO:
     Direct cli support, i.e, yolov8 classify_train args.epochs 10