Add bash install script

rake/pkg/bash.rake

@@ -0,0 +1,30 @@
+desc "Ensure bash is setup & up-to-date"
+task :bash => 'bash:update'
+
+namespace :bash do
+  task :install do
+    if is_mac?
+      echo "Attempting to install bash + completion"
+      Package.install "bash"
+      Package.install "bash-completion"
+
+      # Write the new bash into shells if it isn't already there
+      bash_bin = "/usr/local/bin/bash"
+      if `cat /etc/shells | grep "^#{bash_bin}$"`
+        echo "Writing '#{bash_bin}' to /etc/shells", 2
+        sh_safe "echo '#{bash_bin}' | sudo tee -a /etc/shells"
+      end
+
+      sh_safe "chsh -s #{bash_bin}"
+    end
+  end
+
+  task :update => "bash:install"
+
+  task :remove do
+    if is_mac?
+      Package.remove "bash"
+      Package.remove "bash-completion"
+    end
+  end
+end