ERROR: Unable to download webpage: HTTP Error 400: Bad Request (caused by HTTPError())

[leogao]

$~/youtube-dl https://www.youtube.com/watch?x-yt-cl=84503534&v=bJNGij15w0A&x-yt-ts=1421914688
[1] 8351
[2] 8352
-bash: x-yt-ts=1421914688: command not found
[2]+ Done v=bJNGij15w0A
$[generic] watch?x-yt-cl=84503534: Requesting header
[redirect] Following redirect to https://www.youtube.com/supported_browsers?next_url=%2F
[download] Downloading playlist: supported_browsers
[youtube:user] supported_browsers: Downloading video ids from 1 to 51
ERROR: Unable to download webpage: HTTP Error 400: Bad Request (caused by HTTPError()); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

[1]+ Exit 1 ~/youtube-dl https://www.youtube.com/watch?x-yt-cl=84503534

[naglis]

Your URL contains unescaped ampersands which have a special meaning (to run the command in background) in bash (your shell), so the URL gets cut off. Notice the weird output in the beginning:

[1] 8351
[2] 8352
-bash: x-yt-ts=1421914688: command not found
[2]+ Done v=bJNGij15w0A

This is the output from bash trying to interpret and run the cut off parts of the URL.

To solve this issue, either escape the ampersands with backslashes (\), like this:

youtube-dl https://www.youtube.com/watch?x-yt-cl=84503534\&v=bJNGij15w0A\&x-yt-ts=1421914688

on enclose the URL in single or double quotes:

youtube-dl 'https://www.youtube.com/watch?x-yt-cl=84503534&v=bJNGij15w0A&x-yt-ts=1421914688'

Once you've done that, it should work fine.

Also, next time please include the full output of the command when run with --verbose flag, as outlined here.

[leogao]

OK, enclose the url in single or double quotes, it works well.
Thanks.