Quick reference to displaying blocks based on page or user or role

As a newbie to drupal, I found this info in various places on the forum, but here's a quick reference on how-to-do-it, rather than a philosophical discussion :)

RESTRICT A BLOCK TO ONLY THE FRONT PAGE

create the block as a PHP block with the following code:

if ($_GET["q"] == variable_get("site_frontpage", "node")) {
  return t("this block only appears on the front page");
}

RESTRICT A BLOCK TO ONLY A PARTICULAR ROLE

print_r($user) is a handy command to use if you want to see all the attributes besides role that you can use here.

Create the block as a PHP block with the following code:

global $user;

$role = $user->role;

if ($role == "full administrators") {
  return t("This content will appear to members of role: $role");
}

RESTRICT A BLOCK TO A PARTICULAR PAGE

Surf to the page, note the contents after the q= line

Create the block and save it

In the path for the block on the main block page, enter the path noted above with a leading slash.

For example, the news page would be: </import>

node 9 would be: </node/view/9>

You can use a regular expression here if you would like.

These all work fine in my 4.2 portal without clean URL's. Comments appreciated.