guard works with growl

Gemfile

@@ -3,3 +3,4 @@ source "https://rubygems.org"
 
 gem "guard-shell"
 gem 'rb-fsevent', '~> 0.9.1'
+gem 'growl'

Gemfile.lock

@@ -2,6 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     coderay (1.0.8)
+    growl (1.0.3)
     guard (1.5.4)
       listen (>= 0.4.2)
       lumberjack (>= 1.0.2)
@@ -24,5 +25,6 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  growl
   guard-shell
   rb-fsevent (~> 0.9.1)

Guardfile

@@ -4,7 +4,13 @@
 # Add files and commands to this file, like the example:
 #   watch(%r{file/path}) { `command(s)` }
 #
-guard 'shell' do
-  watch(/(.*).c/) {|m| `make` }
+guard 'shell', all_on_start: true do
+  watch(/(.*).c$/) do |m|
+    if system("make")
+      n "#{m[0]} valid", "Make succeeded", :success
+    else
+      n "Error in #{m[0]}", "Make failed", :failed
+    end
+  end
   watch(/Makefile/) {|m| `make` }
 end