```ruby
require 'knife-cloudformation'

module KnifeCloudformation
  module Utils

    # Helper methods for SSH interactions
    module Ssher

      # Retrieve file from remote node
      #
      # @param address [String]
      # @param user [String]
      # @param path [String] remote file path
      # @param ssh_opts [Hash]
      # @return [String, NilClass]
      def remote_file_contents(address, user, path, ssh_opts={})
        require 'net/ssh'
        content = ''
        ssh_session = Net::SSH.start(address, user, ssh_opts)
        content = ssh.exec!("sudo cat #{path}")
        content.empty? ? nil : content
      end

    end
  end
end
```

Add path check to prevent hang on cat
user
```ruby
require 'knife-cloudformation'

module KnifeCloudformation
  module Utils

    # Helper methods for SSH interactions
    module Ssher

      # Retrieve file from remote node
      #
      # @param address [String]
      # @param user [String]
      # @param path [String] remote file path
      # @param ssh_opts [Hash]
      # @return [String, NilClass]
      def remote_file_contents(address, user, path, ssh_opts={})
        if(path.to_s.strip.empty?)
          raise ArgumentError.new 'No file path provided!'
        end
        require 'net/ssh'
        content = ''
        ssh_session = Net::SSH.start(address, user, ssh_opts)
        content = ssh_session.exec!("sudo cat #{path}")
        content.empty? ? nil : content
      end

    end
  end
end
```
assistant