What does "$<" & "$>" mean in Perl

Question

An example will be highly appreciated. Below is a sample of where I read it:

$self->parameter(
    name => 'real_user',
    xpath => undef, 
    default => scalar(getpwuid($<))
);
$self->parameter(
    name => 'production',
    xpath => '/config/production', 
    default => $self->get('user_uid') == $>
);

Answer 1

A $ followed by symbol? To perlvar!

$<
The real uid of this process.

$>
The effective uid of this process.

Use them to find out what user is running the program.