Convert .mp4 to .ogg keeping only the audio, with Ubuntu 14.04 and avconv

How to convert a .mp4 file (downloaded from YouTube) to .ogg? (keeping only the audio)

When Ubuntu had ffmpeg I could just do ffmpeg -i file.mp4 -acodec vorbis file.ogg

Now we have to do without ffmpeg, but avconv seems to have a different syntax:

$ avconv -i file.mp4 -nv file.ogg
Unrecognized option 'nv'.
Error splitting the argument list: Option not found

Solution 1:

@Nicolas Raoul you made a little mistake, it's not -nv it's -vn try:

avconv -i file.mp4 -vn file.ogg

it will work.