Recurse the current directory and run git gc on all bare repositories.

_gc_bare.rb

#!/usr/bin/env ruby

# A simple script that recurses through the current directory and runs
# git garbage collection on the bare repositories

Dir.glob("**/*.git") do |dir|
  working_dir = File.expand_path dir
  puts "#{dir} being garbage collected."
  `cd #{working_dir};git gc --aggressive --prune --quiet`
end