Add option --alias

yt_dlp/__init__.py

@@ -4,6 +4,7 @@ f'You are using an unsupported version of Python. Only Python versions 3.6 and a
 __license__ = 'Public Domain'
 
 import itertools
+import optparse
 import os
 import re
 import sys
@@ -45,11 +46,18 @@ from .utils import (
     setproctitle,
     std_headers,
     traverse_obj,
+    variadic,
     write_string,
 )
 from .YoutubeDL import YoutubeDL
 
 
+def _exit(status=0, *args):
+    for msg in args:
+        sys.stderr.write(msg)
+    raise SystemExit(status)
+
+
 def get_urls(urls, batchfile, verbose):
     # Batch file verification
     batch_urls = []
@@ -66,7 +74,7 @@ def get_urls(urls, batchfile, verbose):
             if verbose:
                 write_string('[debug] Batch file urls: ' + repr(batch_urls) + '\n')
         except OSError:
-            sys.exit('ERROR: batch file %s could not be read' % batchfile)
+            _exit(f'ERROR: batch file {batchfile} could not be read')
     _enc = preferredencoding()
     return [
         url.strip().decode(_enc, 'ignore') if isinstance(url, bytes) else url.strip()
@@ -810,10 +818,10 @@ def _real_main(argv=None):
     if opts.dump_user_agent:
         ua = traverse_obj(opts.headers, 'User-Agent', casesense=False, default=std_headers['User-Agent'])
         write_string(f'{ua}\n', out=sys.stdout)
-        sys.exit(0)
+        return
 
     if print_extractor_information(opts, all_urls):
-        sys.exit(0)
+        return
 
     with YoutubeDL(ydl_opts) as ydl:
         actual_use = all_urls or opts.load_info_filename
@@ -827,13 +835,13 @@ def _real_main(argv=None):
             # If updater returns True, exit. Required for windows
             if run_update(ydl):
                 if actual_use:
-                    sys.exit('ERROR: The program must exit for the update to complete')
-                sys.exit()
+                    return 100, 'ERROR: The program must exit for the update to complete'
+                return
 
         # Maybe do nothing
         if not actual_use:
             if opts.update_self or opts.rm_cachedir:
-                sys.exit()
+                return
 
             ydl.warn_if_short_id(sys.argv[1:] if argv is None else argv)
             parser.error(
@@ -842,30 +850,30 @@ def _real_main(argv=None):
 
         try:
             if opts.load_info_filename is not None:
-                retcode = ydl.download_with_info_file(expand_path(opts.load_info_filename))
+                return ydl.download_with_info_file(expand_path(opts.load_info_filename))
             else:
-                retcode = ydl.download(all_urls)
+                return ydl.download(all_urls)
         except DownloadCancelled:
             ydl.to_screen('Aborting remaining downloads')
-            retcode = 101
-
-    sys.exit(retcode)
+            return 101
 
 
 def main(argv=None):
     try:
-        _real_main(argv)
+        _exit(*variadic(_real_main(argv)))
     except DownloadError:
-        sys.exit(1)
+        _exit(1)
     except SameFileError as e:
-        sys.exit(f'ERROR: {e}')
+        _exit(f'ERROR: {e}')
     except KeyboardInterrupt:
-        sys.exit('\nERROR: Interrupted by user')
+        _exit('\nERROR: Interrupted by user')
     except BrokenPipeError as e:
         # https://docs.python.org/3/library/signal.html#note-on-sigpipe
         devnull = os.open(os.devnull, os.O_WRONLY)
         os.dup2(devnull, sys.stdout.fileno())
-        sys.exit(f'\nERROR: {e}')
+        _exit(f'\nERROR: {e}')
+    except optparse.OptParseError as e:
+        _exit(2, f'\n{e}')
 
 
 from .extractor import gen_extractors, list_extractors