Dataset download bash script updates (#1132)

data/scripts/get_coco.sh

@@ -8,14 +8,17 @@
 #     /yolov5
 
 # Download/unzip labels
-echo 'Downloading COCO 2017 labels ...'
 d='../' # unzip directory
-f='coco2017labels.zip' && curl -L https://github.com/ultralytics/yolov5/releases/download/v1.0/$f -o $f
-unzip -q $f -d $d && rm $f
+url=https://github.com/ultralytics/yolov5/releases/download/v1.0/
+f='coco2017labels.zip'                                                                 # 68 MB
+echo 'Downloading' $url$f ' ...' && curl -L $url$f -o $f && unzip -q $f -d $d && rm $f # download, unzip, remove
 
 # Download/unzip images
-echo 'Downloading COCO 2017 images ...'
 d='../coco/images' # unzip directory
-f='train2017.zip' && curl http://images.cocodataset.org/zips/$f -o $f && unzip -q $f -d $d && rm $f # 19G, 118k images
-f='val2017.zip' && curl http://images.cocodataset.org/zips/$f -o $f && unzip -q $f -d $d && rm $f   # 1G, 5k images
-# f='test2017.zip' && curl http://images.cocodataset.org/zips/$f -o $f && unzip -q $f -d $d && rm $f  # 7G,  41k images
+url=http://images.cocodataset.org/zips/
+f1='train2017.zip' # 19G, 118k images
+f2='val2017.zip'   # 1G, 5k images
+f3='test2017.zip'  # 7G, 41k images (optional)
+for f in $f1 $f2; do
+  echo 'Downloading' $url$f ' ...' && curl -L $url$f -o $f && unzip -q $f -d $d && rm $f # download, unzip, remove
+done