diff --git a/chrome/content/vimperator/commands.js b/chrome/content/vimperator/commands.js
index bee3af2a..51fd41ef 100644
--- a/chrome/content/vimperator/commands.js
+++ b/chrome/content/vimperator/commands.js
@@ -1032,7 +1032,7 @@ function Commands() //{{{
                   "<code class=\"command\">:set option!</code> and <code class=\"command\">:set invoption</code> invert the value of a boolean option.<br/>" +
                   "<code class=\"command\">:set option?</code> or <code class=\"command\">:set option</code>(for string and list options) shows the current value of an option.<br/>" +
                   "<code class=\"command\">:set option&amp;</code> resets an option to its default value.<br/>" +
-                  "<code class=\"command\">:set option+=foo</code> and <code class=\"command\">:set option-=foo</code> add/remove 'foo' from a string option.<br/>",
+                  "<code class=\"command\">:set option+={value}</code> and <code class=\"command\">:set option-={value}</code> will add/subtract {value} to a number option and append/remove {value} to a string option.<br/>",
             completer: function(filter) { return vimperator.completion.get_options_completions(filter); }
         }
     ));