add '--write-srt' and '--srt-lang' aliases for backwards compatibility

youtube_dl/__init__.py

@@ -173,7 +173,7 @@ def parseOpts():
             action='store', dest='format_limit', metavar='FORMAT', help='highest quality format to download')
     video_format.add_option('-F', '--list-formats',
             action='store_true', dest='listformats', help='list all available formats (currently youtube only)')
-    video_format.add_option('--write-sub',
+    video_format.add_option('--write-sub', '--write-srt',
             action='store_true', dest='writesubtitles',
             help='write subtitle file (currently youtube only)', default=False)
     video_format.add_option('--only-sub',
@@ -188,7 +188,7 @@ def parseOpts():
     video_format.add_option('--sub-format',
             action='store', dest='subtitlesformat', metavar='LANG',
             help='subtitle format [srt/sbv] (default=srt) (currently youtube only)', default='srt')
-    video_format.add_option('--sub-lang',
+    video_format.add_option('--sub-lang', '--srt-lang',
             action='store', dest='subtitleslang', metavar='LANG',
             help='language of the subtitles to download (optional) use IETF language tags like \'en\'')