chef

https://github.com/opscode/chef

Ruby

A systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.

Chef::Node#normal_unless

Set a normal attribute of this node, auto-vivifying any mashes that are
missing, but if the final value already exists, don't set it

Source | Google | Stack overflow

Edit

git clone [email protected]:opscode/chef.git
cd chef
open lib/chef/node.rb

Contribute

# Make a new branch
git checkout -b -your-name--update-docs-Chef--Node-normal_unless-for-pr

# Commit to git
git add lib/chef/node.rbgit commit -m "better docs for Chef::Node#normal_unless"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs-Chef--Node-normal_unless-for-pr
hub pull-request

# Celebrate!