Perl program that takes a list of YouTube URLs and makes markdown links with the video's thumbnail as the link and the video title as the alt text.

ytmarkdown.pl

#!/usr/bin/env perl

use strict ;
use warnings ;
use utf8 ;
use feature qw{ postderef say signatures state } ;
no warnings qw{ experimental::postderef experimental::signatures } ;

use Mojo::UserAgent ;

map { make_md( $_ ) } @ARGV ;

sub make_md ( $string ) {
    return unless $string =~ m{^https?://www.youtube.com}mix ;
    my ( $id ) = $string =~ m{v=([^\?]+)} ;
    my $link   = qq{https://www.youtube.com/watch?v=$id} ;
    my $thumb  = qq{https://img.youtube.com/vi/$id/0.jpg} ;
    my $title  = 'Hover Text' ;

    my $dom = Mojo::UserAgent->new->get( $link )->res->dom ;
    $dom->find( 'title' )->each(
        sub {
            my $e = $_ ;
            $title = $e->text ;
            }
            ) ;

    say qq{[ ![$title]($thumb)]( $link ) } ;
    }