diff --git a/Library/Homebrew/extend/string.rb b/Library/Homebrew/extend/string.rb
index 632d8ae8a3..1d9c2e0360 100644
--- a/Library/Homebrew/extend/string.rb
+++ b/Library/Homebrew/extend/string.rb
@@ -21,6 +21,10 @@ class String
     s = chomp
     s unless s.empty?
   end
+
+  def strip_prefix(prefix)
+    start_with?(prefix) ? self[prefix.length..-1] : self
+  end
 end
 
 class NilClass