add '--no-colors' command-line option

docs/options.md

@@ -29,6 +29,7 @@
 
 ## Output Options:
     -q, --quiet                 Activate quiet mode
+    -w, --warning               Print only warnings and errors
     -v, --verbose               Print various debugging information
     -g, --get-urls              Print URLs instead of downloading
     -G, --resolve-urls          Print URLs instead of downloading; resolve
@@ -48,12 +49,12 @@
                                 extractors but cannot be handled, to FILE
     --write-pages               Write downloaded intermediary pages to files in
                                 the current directory to debug problems
+    --no-colors                 Do not emit ANSI color codes in output
 
 ## Downloader Options:
     -r, --limit-rate RATE       Maximum download rate (e.g. 500k or 2.5M)
     -R, --retries N             Maximum number of retries for failed HTTP
-                                requests or -1 for infinite retries (default:
-                                4)
+                                requests or -1 for infinite retries (default: 4)
     --http-timeout SECONDS      Timeout for HTTP connections (default: 30.0)
     --sleep SECONDS             Number of seconds to wait before each download.
                                 This can be either a constant value or a range

gallery_dl/__init__.py

@@ -38,6 +38,11 @@ def main():
             except ImportError:
                 import toml
             config.load(args.configs_toml, strict=True, loads=toml.loads)
+        if not args.colors:
+            output.ANSI = False
+            config.set((), "colors", False)
+            if util.WINDOWS:
+                config.set(("output",), "ansi", False)
         if args.filename:
             filename = args.filename
             if filename == "/O":

gallery_dl/option.py

@@ -325,6 +325,11 @@ def build_parser():
         help=("Write downloaded intermediary pages to files "
               "in the current directory to debug problems"),
     )
+    output.add_argument(
+        "--no-colors",
+        dest="colors", action="store_false",
+        help=("Do not emit ANSI color codes in output"),
+    )
 
     downloader = parser.add_argument_group("Downloader Options")
     downloader.add_argument(