[BUG] `--write-sub -o -` writes subtitle to a file named -

[NightMachinary]

Checklist

• I'm reporting a broken site support issue
• I've verified that I'm running youtube-dl version 2020.05.08
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

Description

--write-sub -o - writes subtitle to a file named -. It should use the video's name or accept a name with a new cli option.

[rafinetiz]

you can't write the output to file named -, as i know, when you pass - to -o option, the output will be written to STDOUT.

and if you mean you want to write subtitle to different name, i think this is not a bug but a feature request.

[NightMachinary]

@rafinetiz the problem is that the video file is going into stdout, so the subtitle file has nowhere to go.

[jrauhamaa]

Same thing seems to happen when format is specified.
$ youtube-dl <url> -o - > video
writes to a file named 'video', while
$ youtube-dl <url> -f <FORMAT> -o - > video
writes the video to '-.mkv'

Somehow the -o - option gets interpreted differently depending on whether format options are provided or not.