How to do it…

Let's find out how knife can help you to look into a cookbook stored in your Chef server:

1. First, you want to find out the current version of the cookbook you're interested in. In our case, we're interested in the iptables cookbook:

   mma@laptop:~/work/chef_helpster $ knife cookbook show iptables
   iptables   3.0.0 0.14.1
   

2. Then, you can look up the definitions of the iptables cookbook, using the version number that you found in the previous step:

   mma@laptop:~/chef-repo $ knife cookbook show iptables 0.14.1 definitions
     checksum:     45c0b77ff10d7177627694827ce47340
     name:         iptables_rule.rb
     path:         definitions/iptables_rule.rb
     specificity:  default
     url:          https://s3-external-1.amazonaws.com:443/opscode-platform...
   

3. Now, you can even show the contents of the iptables_rule.rb definition file, as stored on the server:

   mma@laptop:~/chef-repo $ knife cookbook show iptables 0.14.1 definitions iptables_rule.rb
   #
   # Cookbook Name:: iptables
   # Definition:: iptables_rule
   #
   #
   define :iptables_rule, :enable => true, :source => nil, :variables => {}, :cookbook => nil do
   ...TRUNCATED OUTPUT...
   end