diff --git a/lib/rscons/basic_environment.rb b/lib/rscons/basic_environment.rb
index 2e18134..65705ae 100644
--- a/lib/rscons/basic_environment.rb
+++ b/lib/rscons/basic_environment.rb
@@ -247,5 +247,28 @@ module Rscons
       end
     end
 
+    # Execute a command using the system shell.
+    #
+    # The shell is automatically determined but can be overridden by the SHELL
+    # construction variable. If the SHELL construction variable is specified,
+    # the flag to pass to the shell is automatically dtermined but can be
+    # overridden by the SHELLFLAG construction variable.
+    #
+    # @param command [String] Command to execute.
+    #
+    # @return [String] The command's standard output.
+    def shell(command)
+      shell_cmd =
+        if shell = get_var("SHELL")
+          flag = get_var("SHELLFLAG") || (shell == "cmd" ? "/c" : "-c")
+          [shell, flag]
+        else
+          Rscons.get_system_shell
+        end
+      IO.popen([*shell_cmd, command]) do |io|
+        io.read
+      end
+    end
+
   end
 end
diff --git a/lib/rscons/configure_op.rb b/lib/rscons/configure_op.rb
index a996534..2bdbc50 100644
--- a/lib/rscons/configure_op.rb
+++ b/lib/rscons/configure_op.rb
@@ -12,11 +12,11 @@ module Rscons
     #
     # @param options [Hash]
     #   Optional parameters.
-    # @param build_dir [String]
+    # @option options [String] :build_dir
     #   Build directory.
-    # @param prefix [String]
+    # @option options [String] :prefix
     #   Install prefix.
-    # @param project_name [String]
+    # @option options [String] :project_name
     #   Project name.
     def initialize(options)
       # Default options.
diff --git a/lib/rscons/environment.rb b/lib/rscons/environment.rb
index fa533e0..3d2c9cd 100644
--- a/lib/rscons/environment.rb
+++ b/lib/rscons/environment.rb
@@ -487,29 +487,6 @@ module Rscons
       end
     end
 
-    # Execute a command using the system shell.
-    #
-    # The shell is automatically determined but can be overridden by the SHELL
-    # construction variable. If the SHELL construction variable is specified,
-    # the flag to pass to the shell is automatically dtermined but can be
-    # overridden by the SHELLFLAG construction variable.
-    #
-    # @param command [String] Command to execute.
-    #
-    # @return [String] The command's standard output.
-    def shell(command)
-      shell_cmd =
-        if shell = get_var("SHELL")
-          flag = get_var("SHELLFLAG") || (shell == "cmd" ? "/c" : "-c")
-          [shell, flag]
-        else
-          Rscons.get_system_shell
-        end
-      IO.popen([*shell_cmd, command]) do |io|
-        io.read
-      end
-    end
-
     # Print the builder run message, depending on the Environment's echo mode.
     #
     # @param builder [Builder]