In scalar context, the match operator and thus the bind operator returns whether a match was found or not. You want to evaluate the match in list context to get it to return the list of matches.

Fix:

   my ($aDate) = $a =~ /\bdate:\s*"(\d{4}-\d{2}-\d{2})"/;
   my ($bDate) = $b =~ /\bdate:\s*"(\d{4}-\d{2}-\d{2})"/;
[download]

Also:

• Added \b to avoid catching enddate.
• Added \s* in case the JSON encoder decides to start adding whitespace.
• Removed some superfluous backslashes.

Note: Will break if you get

• { date:"\u0032015-05-01", content:"erwa" }
• { foo:{date:"2014-05-01"}, date:"2015-05-01", content:"erwa" }
• etc

For a reliable but slower solution, you can use

use JSON::XS qw( decode_json );

my @sorted =
   map { substr($_, 10) }
      sort
         map { decode_json($_)->{date} . $_ }
            @events;
[download]

As for the blank lines, just remove them first using

@events = grep /\S/, @events;
[download]

Update: Added to my answer.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.