1 files changed, 5 insertions, 0 deletions
diff --git a/Library/Formula/git-hg.rb b/Library/Formula/git-hg.rb
index a8634fa79..ac2a4b6d9 100644
--- a/Library/Formula/git-hg.rb
+++ b/Library/Formula/git-hg.rb
@@ -5,6 +5,11 @@ class GitHg < Formula
   homepage 'http://offbytwo.com/git-hg/'
 
   def install
+    unless `/usr/bin/which hg`.size > 0
+      puts "You may need to install Mercurial before using this software:"
+      puts "  brew install mercurial"
+    end
+
     prefix.install Dir['*']
   end
 end