Hi,
I'm not goot at English, but let me explain. I'm using 10.8.2, too.
Have you installed Xcode and Command Line Tools? If not, install Xcode from App Store, then launch Xcode, go to "Preferences... > Downloads" and install Command Line Tools first.
You should download the latest rtmpdump source code by following the instruction on the home page:
Then type, or copy and paste, these 2 lines:
Code:
cd rtmpdump
make SYS=darwin
You'll see a lot of warning messages with "make", but you don't need to care about them, I think.
Then type this line:
Code:
sudo make install SYS=darwin mandir='$(prefix)/share/man'
You may see some warning-like message with "sudo" and will see the "Password:" prompt, there you need to type the administrator password. The password you type can't be seen on the terminal, so please don't worry about that.
rtmpdump will be installed under the /usr/local directory.
As to how to use rtmpdump, read the README, manual page "man rtmpdump" or rtmpdump.1.html, and many threads on this forum.