<?php

/**
 * @author Chris Horeweg in response to http://stackoverflow.com/questions/10248031/php-read-content-and-do-a-preg-match
 */

$content = "@font-face {
  font-family: 'someFonts';
}

@font-face {
  font-family: 'someotherFonts';
}

.style {
  font-family: 'someFonts';
}";
if (!preg_match('#@font-face {([^;]+);#i', $content, $matches)) {
  echo 'Not Found';
}
else {
    echo print_r($matches, true);
}
/** Output:

Array
(
    [0] => @font-face {
  font-family: 'someFonts';
    [1] =>
  font-family: 'someFonts'
)

**/
?>