Preview is not directly scriptable at all, either via shell scripts or AppleScript.
However, AppleScript has some system-wide abilities such as sending keystrokes to applications, therefore you can effect the same actions via something like:
<pre class=command>osascript -e 'tell application "Preview" to activate' -e 'tell application "System Events" to keystroke "n" using {command down}'</pre>
This uses
osascript to run the AppleScript commands that launches Preview and issues Cmd-N, the keyboard equivalent of 'New from Clipboard'.