This is misbehaving (in the sense of not doing what you want; in the strictly technical sense, it's behaving perfectly), because you're assigning localtime to an array. When you do this, you get a nine element array with the following components: ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)

On the other hand, if you assigned it to a scalar, then you'd get a printable string:

$yesterday=localtime(time()-86400);
print $yesterday;
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Wed Dec 18 16:58:19 2002

--
Tommy
Too stupid to live.
Too stubborn to die.