Easy thumbnails of PDFs on OS X

I recently needed to create some thumbnails, using the first page of a fairly large number of PDFs. I was pleasantly surprised to learn that OS X has a handy command-line utility that can be easily scripted to do this. Here’s the one-liner I used to accomplish the task:

for file in `echo *.pdf`; do sips -s format jpeg --resampleWidth 540 \
$file --out `basename $file .pdf`_thumb.jpg; done