git-dag is a ruby script that generates a DAG tree (in the 'dot' format) for a given Git repository.
You need to have Ruby installed. Try RVM or rbenv if you don't have one installed.
You need to have Graphviz installed if you want to render the DAG visually. You can install it using the package manager provided by your OS.
For instance, if you use Mac OS X and have homebrew installed, you can do:
$ brew install graphviz
Easy install with RubyGems:
$ gem install git-dag
To generate a DAG (in the format 'dot') for a Git repository, do
$ git-dag <path_to_git_repo> > history.dot
Use to 'dot' to draw the DAG:
$ dot -Tsvg history.dot -o history.svg
You can pipe the 2 commands together:
$ git-dag <path_to_git_repo> | dot -Tsvg -o history.svg
Note that if it take a good amount of time if your repository has a long history of commits.
Now you can open up 'history.svg' in your browser to see the DAG.
Graphviz supports a lot of other formats, such as jpg, pdf, png, ps2 etc. Please see Graphviz for more info.