@mikewillitsgmail.com:

<?php

$out = sscanf('file_name.gif', 'file_%[^.].%s', $fpart1, $fpart2);

echo '<pre>';
print_r($fpart1);
echo '<hr />';
print_r($fpart2);
echo '</pre>';

?>

output:

name
-
gif

The "^." part avoid the first searched string to be too greedy. But doesn't protect you against an "file_test.name.gif" input, with bad results!