1 files changed, 27 insertions, 0 deletions
diff --git a/Library/Contributions/cmd/brew-leaves.rb b/Library/Contributions/cmd/brew-leaves.rb
new file mode 100755
index 000000000..f94809c9d
--- /dev/null
+++ b/Library/Contributions/cmd/brew-leaves.rb
@@ -0,0 +1,27 @@
+# Outputs formulae that are installed but are not a dependency for
+# any other installed formula.
+# See: http://github.com/mxcl/homebrew/issues/issue/1438
+
+require 'formula'
+
+def get_used_by
+  used_by = {}
+  Formula.each do |f|
+    next if f.deps == nil
+
+    f.deps.each do |dep|
+      _deps = used_by[dep.to_s] || []
+      _deps << f.name unless _deps.include? f.name
+      used_by[dep.to_s] = _deps
+    end
+  end
+
+  return used_by
+end
+
+deps_graph = get_used_by()
+installed = HOMEBREW_CELLAR.children.select { |pn| pn.directory? }.collect { |pn| pn.basename.to_s }
+installed.each do |name|
+  deps = deps_graph[name] || []
+  puts name unless deps.any? { |dep| installed.include? dep.to_s }
+end