There are lot of variables declared in the WordPress, one of the method I used determine this kind of variables is to add this code in the index.php to display all the variables, I usually used this when I do offline development:
<?php
$test_global = get_defined_vars();
foreach ($test_global as $key=>$value){
echo "$key <br />";
}
?>
Looking at the result of the code above I know that $post is a declared variable and also an array. Then we can use foreach loop to determine content of the post variable.
<?php
foreach ($post as $key=>$value){
echo "$key => $value <br />";
}
?>
The result shows the all content of every index in the post array. For a more specific result:
<?php print_r($post->post_title); ?>
thanks