How do I set environment variable completion in a bash shell on mac

In a bash shell on linux, if I type:

echo $DISP

and hit tab, it completes to:

echo $DISPLAY

It doesn't work in bash on OSX 10.5, and I'm using the same .bashrc

Is开发者_C百科 there a shell option or setting I can use to set this.

you may need to install bash_completion from darwin ports (http://bash-completion.darwinports.com/)

I don't know if its what you want, but how about this?