为什么wget返回8？

Question

在以下示例中，

wget返回8。我认为这很正常。但是为什么将其视为wget中的错误？ （curl是否还会返回错误？我不熟悉curl的选项。有人可以显示等效的curl命令进行比较吗？）有人可以帮助我理解吗？谢谢。

$ wget --no-check-certificate -U 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36' -q -O /dev/null -S -o- --max-redirect 0 'http://rs.yiigle.com/CN112137199605/837055.htm?locale=zh_CN'
  HTTP/1.1 302 Found
  Date: Sat, 02 Nov 2019 03:04:46 GMT
  Content-Type: text/html
  Content-Length: 0
  Connection: keep-alive
  Set-Cookie: AWSALB=QKnd0TCubtc+KRKge13/Ixg7Rll6QxblaaMDKpVEZvRR7+4QoYWuGV1FhA4NOChU/mO8YVRJuqfTAuweA4zxUpQECAzEgTMBjB6+cUzqv5hxezv6mRu3flCGnspH; Expires=Sat, 09 Nov 2019 03:04:46 GMT; Path=/
  Server: Apache-Coyote/1.1
  Location: http://cas.medline.org.cn?service=http%3A%2F%2Frs.yiigle.com%3A80%2FCN112137199605%2F837055.htm%3Flocale%3Dzh_CN&gateway=true&loginUrl=%2F
  Set-Cookie: JSESSIONID=77DBCC76091CA02135CB99B5DC95251C; Path=/; HttpOnly
$ echo "$?"
8