Rename `date_format` to template

Clearer for the user.

Inst_eddies/inst_eddies_in.py

@@ -15,7 +15,7 @@ argparser = argparse.ArgumentParser()
 argparser.add_argument("first_file",
                        help = "NetCDF file containing SSH and velocity at a "
                        "single date")
-argparser.add_argument("date_format",
+argparser.add_argument("template",
                        help = "template of basename with date format")
 argparser.add_argument("-l", "--last_date", help = "%%Y-%%m-%%d")
 argparser.add_argument("-b", "--bbox", nargs=4, type = float,
@@ -35,7 +35,7 @@ for orient in ["cyclo", "anti"]:
         shutil.rmtree(f"SHPC_{orient}_all_dates")
         
 dirname, basename = path.split(args.first_file)
-my_date = datetime.datetime.strptime(basename, args.date_format).date()
+my_date = datetime.datetime.strptime(basename, args.template).date()
 nc_file = args.first_file
 nco_instance = nco.Nco()
 
@@ -96,7 +96,7 @@ while True:
 
     my_date += datetime.timedelta(1)
     if my_date > last_date: break
-    basename = my_date.strftime(args.date_format)
+    basename = my_date.strftime(args.template)
     nc_file = path.join(dirname, basename)
 
 os.remove("unpacked.nc")