1 files changed, 103 insertions, 0 deletions
diff --git a/lib/chef/knife/help.rb b/lib/chef/knife/help.rb
new file mode 100644
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+++ b/lib/chef/knife/help.rb
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+#
+# Author:: Daniel DeLeo (<dan@opscode.com>)
+# Copyright:: Copyright (c) 2011 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.
+#
+
+class Chef
+  class Knife
+    class Help < Chef::Knife
+
+      banner "knife help [list|TOPIC]"
+
+      def run
+        if name_args.empty?
+          ui.info "Usage: knife SUBCOMMAND (options)"
+          ui.msg ""
+          # This command is atypical, the user is likely not interested in usage of
+          # this command, but knife in general. So hack the banner.
+          opt_parser.banner = "General Knife Options:"
+          ui.msg opt_parser.to_s
+          ui.msg ""
+          ui.info "For further help:"
+          ui.info(<<-MOAR_HELP)
+  knife help list             list help topics
+  knife help knife            show general knife help
+  knife help TOPIC            display the manual for TOPIC
+  knife SUBCOMMAND --help     show the options for a command
+MOAR_HELP
+          exit 1
+        else
+          @query = name_args.join('-')
+        end
+
+
+
+        case @query
+        when 'topics', 'list'
+          print_help_topics
+          exit 1
+        when 'intro', 'knife'
+          @topic = 'knife'
+        else
+          @topic = find_manpages_for_query(@query)
+        end
+
+        manpage_path = find_manpage_path(@topic)
+        exec "man #{manpage_path}"
+      end
+
+      def help_topics
+        # The list of help topics is generated by a rake task from the available man pages
+        # This constant is provided in help_topics.rb which is automatically required/loaded by the knife subcommand loader.
+        HELP_TOPICS
+      end
+
+      def print_help_topics
+        ui.info "Available help topics are: "
+        help_topics.collect {|t| t.gsub(/knife-/, '') }.sort.each do |topic|
+          ui.msg "  #{topic}"
+        end
+      end
+
+      def find_manpages_for_query(query)
+        possibilities = help_topics.select do |manpage|
+          ::File.fnmatch("knife-#{query}*", manpage) || ::File.fnmatch("#{query}*", manpage)
+        end
+        if possibilities.empty?
+          ui.error "No help found for '#{query}'"
+          ui.msg ""
+          print_help_topics
+          exit 1
+        elsif possibilities.size == 1
+          possibilities.first
+        else
+          ui.info "Multiple help topics match your query. Pick one:"
+          ui.highline.choose(*possibilities)
+        end
+      end
+
+      def find_manpage_path(topic)
+        if ::File.exists?(::File.expand_path("../distro/common/man/man1/#{topic}.1", CHEF_ROOT))
+          # If we've provided the man page in the gem, give that
+          return ::File.expand_path("../distro/common/man/man1/#{topic}.1", CHEF_ROOT)
+        else
+          # Otherwise, we'll just be using MANPATH
+          topic
+        end
+      end
+    end
+  end
+end