Generate a graph of Homebrew dependencies

Firstly, ensure that graphviz is installed with brew install graphviz.

You'll need to somehow get the graph command in one of two ways:

1. Tap the boneyard with brew tap homebrew/boneyard. This will install an older version of the command, written in Python that parses brew deps. It may stop working as time goes on.
2. Copy the brew-graph script from this project to somewhere on your PATH. It hasn't been updated in a while, so YMMV. You will have to write the data to a file with -o filename and modify the command below to read from that file until issue #2 is fixed.

Then you can do this with the Python version:

brew graph | dot -Tgif > deps.gif

Or this with the Ruby version:

brew graph -g all -o graph.dot
cat graph.dot | dot -Tgif > deps.gif
open deps.gif

This will generate something like this:

Use gif instead of png for this, as the image is only a few colors and otherwise ends up being huge.