CKEDITOR.editorConfig = function( config )
{
// Define changes to default configuration here. For example:
//config.language = 'fr';
//config.uiColor = '#AADC6E';
config.toolbar_Full = [
{ name: 'document', items : [ 'Source'] },
{ name: 'clipboard', items : [ 'Cut','Copy','Paste','PasteText','PasteFromWord','-','Undo','Redo' ] },

{ name: 'basicstyles', items : [ 'Bold','Italic','Underline','Strike','Subscript','Superscript','-','RemoveFormat' ] },
{ name: 'paragraph', items : [ 'NumberedList','BulletedList','-','Outdent','Indent','-','Blockquote','-','JustifyLeft','JustifyCenter','JustifyRight','JustifyBlock' ] },
{ name: 'links', items : [ 'Link','Unlink','Anchor' ] },
{ name: 'insert', items : [ 'Image','Table','HorizontalRule','SpecialChar'] },

{ name: 'styles', items : [ 'Format','Font','FontSize' ] },
{ name: 'colors', items : [ 'TextColor','BGColor' ] }
];

//Integration with ckFinder
//config.filebrowserBrowseUrl = 'ckfinder/ckfinder.html';
//config.filebrowserImageBrowseUrl = 'ckfinder/ckfinder.html?Type=Images';
//config.filebrowserFlashBrowseUrl = 'ckfinder/ckfinder.html?Type=Flash';
//config.filebrowserUploadUrl = 'ckfinder/core/connector/php/connector.php?command=QuickUpload&type=Files'; //可上傳一般檔案
config.filebrowserImageUploadUrl = 'ckfinder/core/connector/php/connector.php?command=QuickUpload&type=Images';//可上傳圖檔
//config.filebrowserFlashUploadUrl = 'ckfinder/core/connector/php/connector.php?command=QuickUpload&type=Flash';//可上傳Flash檔案

//Add font family
config.font_names = config.font_names + ';標楷體;微軟正黑體;新細明體;';
};

Reference:

1. http://ckeditor.com/latest/samples/plugins/toolbar/toolbar.html