Where can I find my (current shell process') PID?

I'm on OS X using ZSH (have lots of homebrew stuff, too).

I'd like to know the PID of my current terminal.

(I'm learning more about process management on *nix systems, pstree and the like, and so this is more an academic question vs. a specific use case I'm trying to solve)

EDIT: to clarify, I'm referring to the process that is running my current terminal/commandline.

1 Answer

The special variable $$ is the current pid of the shell you are running, for any Bourne compatible (and, so, POSIX) shell.