```ruby
#
# Author:: Stephen Delano (<stephen@opscode.com>)
# Copyright:: Copyright (c) 2010 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'chef/knife'

class Chef
  class Knife
    class EnvironmentShow < Knife

      deps do
        require 'chef/environment'
        require 'chef/json_compat'
      end

      banner "knife environment show ENVIRONMENT (options)"

      def run
        env_name = @name_args[0]

        if env_name.nil?
          show_usage
          ui.fatal("You must specify an environment name")
          exit 1
        end

        env = Chef::Environment.load(env_name)
        output(format_for_display(env))
      end
    end
  end
end
```

Add -a option to knife environment show command.
user
```ruby
#
# Author:: Stephen Delano (<stephen@opscode.com>)
# Copyright:: Copyright (c) 2010 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'chef/knife'

class Chef
  class Knife
    class EnvironmentShow < Knife

      deps do
        require 'chef/environment'
        require 'chef/json_compat'
      end

      @attrs_to_show = []
      option :attribute,
        :short => "-a [ATTR]",
        :long => "--attribute [ATTR]",
        :proc => lambda {|val| @attrs_to_show << val},
        :description => "Show one or more attributes"

      banner "knife environment show ENVIRONMENT (options)"

      def run
        env_name = @name_args[0]

        if env_name.nil?
          show_usage
          ui.fatal("You must specify an environment name")
          exit 1
        end

        env = Chef::Environment.load(env_name)
        output(format_for_display(env))
      end
    end
  end
end
```
assistant