diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 52f3dd6a86..05fc144e2d 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -38,6 +38,10 @@ else
   HOMEBREW_CACHE=Pathname.new("~/Library/Caches/Homebrew").expand_path
 end
 
+if not defined? HOMEBREW_BREW_FILE
+  HOMEBREW_BREW_FILE = ENV['HOMEBREW_BREW_FILE'] or `which brew`.chomp
+end
+
 HOMEBREW_PREFIX = Pathname.new(HOMEBREW_BREW_FILE).dirname.parent # Where we link under
 HOMEBREW_REPOSITORY = Pathname.new(HOMEBREW_BREW_FILE).realpath.dirname.parent # Where .git is found
 
diff --git a/Library/Homebrew/install.rb b/Library/Homebrew/install.rb
index 887705e707..24fb82148b 100755
--- a/Library/Homebrew/install.rb
+++ b/Library/Homebrew/install.rb
@@ -1,6 +1,4 @@
 #!/usr/bin/ruby
-HOMEBREW_BREW_FILE = `which brew`.strip
-
 require 'global'
 
 def text_for_keg_only_formula f
diff --git a/bin/brew b/bin/brew
index 57352b4a14..ccb46f3a63 100755
--- a/bin/brew
+++ b/bin/brew
@@ -6,6 +6,7 @@
 Dir.getwd rescue abort "The current working directory doesn't exist, cannot proceed."
 
 HOMEBREW_BREW_FILE = File.expand_path __FILE__
+ENV['HOMEBREW_BREW_FILE'] = HOMEBREW_BREW_FILE
 
 def homebrew_rubylib_path
   lib_path = "/../../Library/Homebrew"