Improved the output of --help for bam.pack

bam/blend/blendfile_pack.py

@@ -588,7 +588,8 @@ def create_argparse():
 
     parser = argparse.ArgumentParser(
         description="Run this script to extract blend-files(s) and their dependencies "
-                    "to a destination path.")
+                    "to a destination path.",
+                    formatter_class=argparse.RawTextHelpFormatter)
 
     # for main_render() only, but validate args.
     parser.add_argument(
@@ -598,15 +599,21 @@ def create_argparse():
     parser.add_argument(
             "-e", "--exclude", dest="exclude", metavar='PATTERN', required=False,
             help='Exclusion pattern, such as "*.abc;*.mov;*.mkv"')
-    parser.add_argument(
-            "-o", "--output", dest="path_dst", metavar='DIR', required=True,
-            help="Output file (must be a .blend for --mode=FILE or a .zip when --mode=ZIP), "
-                 "or a directory when multiple inputs are passed",
-            )
     parser.add_argument(
             "-m", "--mode", dest="mode", metavar='MODE', required=False,
             choices=('FILE', 'ZIP'), default='ZIP',
-            help="FILE copies the blend file(s) + dependencies to a directory, ZIP to an archive.",
+            help='''Output mode (default:ZIP)
+ZIP: copies to an archive
+FILE: copies single input to a blend file and multiple input files to a directory''',
+            )
+    parser.add_argument(
+            "-o", "--output", dest="path_dst", metavar='DIR', required=True,
+            help='''The output file must match to the --mode parameter:
+for mode FILE:
+    - a .blend for single input file
+    - a directory when multiple inputs are passed
+for mode ZIP:
+    - a zip file''',
             )
     parser.add_argument(
             "-q", "--quiet", dest="use_quiet", action='store_true', required=False,