It is a very simple operation that can be effectively used inside shell scripts.
$! special parameter to get the process ID of the most recently executed background command.
$ find . -name 2014-* -fprint articles.2014 &  1634
$ echo $! 1634
See Special Parameters section of the
bash manual page for further reference.
As a side note, I will mention How to open manual page at the specific page section blog post I wrote more than a year ago.