Question: I want to download any videos form any site using terminal command , I know "`youtube-dl`" but it doesn't download videos from some sites like khan academy so, what is the best for that ?

Answer: 
You can also use `youtube-dl` for that. Just copy the url of the video. In case you don't know about the link. Just right click & see **View Frame Info** you'll see the video url there. Then

```
youtube-dl videourl

```
You could use this:

```
wget --force-yes "'echo$http:url'" 

```

and it might work fine this way.