How do I determine the process id of the current bash shell?

[indigowinged]

Man page for bash - GNU Bourne-Again SHell

Display the process id of the current shell, can be used within a shell script.

echo $$
2240

Verify by using the usual way of checking your running process.

$ ps
  PID TTY          TIME CMD
 2240 pts/0    00:00:00 bash
 2301 pts/0    00:00:00 ps