Add option --no-cache-dir

youtube_dl/__init__.py

@@ -167,7 +167,12 @@ def parseOpts(overrideArguments=None):
             help='Output descriptions of all supported extractors', default=False)
     general.add_option('--proxy', dest='proxy', default=None, help='Use the specified HTTP/HTTPS proxy', metavar='URL')
     general.add_option('--no-check-certificate', action='store_true', dest='no_check_certificate', default=False, help='Suppress HTTPS certificate validation.')
-    general.add_option('--cache-dir', dest='cachedir', default=u'~/.youtube-dl/cache', help='Location in the filesystem where youtube-dl can store downloaded information permanently. NONE to disable filesystem caching, %default by default')
+    general.add_option(
+        '--cache-dir', dest='cachedir', default=u'~/.youtube-dl/cache',
+        help='Location in the filesystem where youtube-dl can store downloaded information permanently. %default by default')
+    general.add_option(
+        '--no-cache-dir', action='store_const', const=None, dest='cachedir',
+        help='Disable filesystem caching')
 
 
     selection.add_option('--playlist-start',
@@ -560,7 +565,7 @@ def _real_main(argv=None):
         parser.error(u'Cannot download a video and extract audio into the same'
                      u' file! Use "%%(ext)s" instead of %r' %
                      determine_ext(outtmpl, u''))
-
+    raise ValueError(repr(opts.cachedir))
     # YoutubeDL
     ydl = YoutubeDL({
         'usenetrc': opts.usenetrc,
@@ -618,7 +623,7 @@ def _real_main(argv=None):
         'min_filesize': opts.min_filesize,
         'max_filesize': opts.max_filesize,
         'daterange': date,
-        'cachedir': opts.cachedir if opts.cachedir != 'NONE' else None,
+        'cachedir': opts.cachedir,
         'youtube_print_sig_code': opts.youtube_print_sig_code,
         })