add verbose flag and dev-instructions

scripts/capture_csv.py

@@ -78,6 +78,12 @@ def main() -> int:
         default=True,
         help="Send 'log on' to the dryer after connect (default: on)",
     )
+    parser.add_argument(
+        "-v",
+        "--verbose",
+        action="store_true",
+        help="Echo captured CSV rows to stdout; other serial lines to stderr",
+    )
     args = parser.parse_args()
 
     port = args.port
@@ -125,22 +131,32 @@ def main() -> int:
 
             line = raw.decode("utf-8", errors="replace").strip()
             if not line.startswith("csv_hdr,") and not line.startswith("csv,"):
+                if args.verbose and line:
+                    print(line, file=sys.stderr)
                 continue
 
             if line.startswith("csv_hdr,"):
                 device_header = line[len("csv_hdr,") :]
-                fh.write("wall_time," + device_header + "\n")
+                row = "wall_time," + device_header
+                fh.write(row + "\n")
                 header_written = True
                 fh.flush()
+                if args.verbose:
+                    print(row)
                 continue
 
             if not header_written:
                 fh.write(FALLBACK_HEADER + "\n")
                 header_written = True
+                if args.verbose:
+                    print(FALLBACK_HEADER)
 
             wall_time = datetime.now(timezone.utc).isoformat(timespec="seconds")
-            fh.write(wall_time + "," + line[len("csv,") :] + "\n")
+            row = wall_time + "," + line[len("csv,") :]
+            fh.write(row + "\n")
             fh.flush()
+            if args.verbose:
+                print(row)
 
 
 if __name__ == "__main__":