dvc: std/update --tragets options

to match iterative/dvc.org/pull/2062

Author: jorgeorpinel

dvc/command/diff.py

@@ -174,9 +174,10 @@ def add_parser(subparsers, parent_parser):
         "--targets",
         nargs="*",
         help=(
-            "Limit command scope to these tracked files or directories. "
+            "Specific DVC-tracked files to compare. "
             "Accepts one or more file paths."
         ),
+        metavar="<paths>",
     ).complete = completion.FILE
     diff_parser.add_argument(
         "a_rev",

dvc/command/metrics.py

@@ -280,8 +280,11 @@ def add_parser(subparsers, parent_parser):
         "--targets",
         nargs="*",
         help=(
-            "Limit command scope to these metrics files. Using -R, "
-            "directories to search metrics files in can also be given."
+            "Specific metrics file(s) to compare "
+            "(even if not found as `metrics` in `dvc.yaml`). "
+            "Using -R, directories to search metrics files in "
+            "can also be given."
+            "Shows all tracked metrics by default.",
         ),
         metavar="<paths>",
     ).complete = completion.FILE

dvc/command/params.py

@@ -98,8 +98,12 @@ def add_parser(subparsers, parent_parser):
     params_diff_parser.add_argument(
         "--targets",
         nargs="*",
-        help="Limit command scope to these params files.",
-        metavar="<path>",
+        help=(
+            "Specific params file(s) to compare "
+            "(even if not found as `params` in `dvc.yaml`). "
+            "Shows all tracked params by default.",
+        ),
+        metavar="<paths>",
     ).complete = completion.FILE
     params_diff_parser.add_argument(
         "--all",

dvc/command/plots.py

@@ -158,10 +158,12 @@ def add_parser(subparsers, parent_parser):
     plots_diff_parser.add_argument(
         "--targets",
         nargs="*",
-        help="Files to visualize (supports any file, "
-        "even when not found as `plots` in `dvc.yaml`). "
-        "Shows all plots by default.",
-        metavar="<path>",
+        help=(
+            "Specific plots file(s) to visualize "
+            "(even if not found as `plots` in `dvc.yaml`). "
+            "Shows all tracked plots by default.",
+        ),
+        metavar="<paths>",
     ).complete = completion.FILE
     plots_diff_parser.add_argument(
         "-e",