Added the -o option to allow more SSH options

The -o option will allow users to specify an ssh key or any other ssh parameter to CSSH from the command line
-o will take precedence over the -l parameter
Added in code to print the help message when no parameters were passed

Author: h2o8polo

README.md

@@ -27,12 +27,14 @@ Note:  Mac users with the latest version of XCode may run into a compilation err
         -l, --login [USER]               Log in with this user
         -t, --tags [TAGS]                a 'space' sparated key value pair of tags and values (i.e. -t 'role=web,database environment=dev')
         -r, --region [REGION]            AWS region
+        -o, --options [SSH_OPTIONS]      ssh options to pass directly to cssh
         -s, --screen [SCREEN]            What screen to use for clustering windows (form multiple displays)
         -p, --use-public-ip              Use public IP (default false)
 
 
     $cluster -t Name=web,database                  #Connects to all web and database servers
     $cluster -t 'role=web,database environment=dev'  #Connects to all web and database servers in the dev environment
+    $cluster -t 'role=web,database environment=dev' -o"-i /Path/to/key.pem"  # connect using explicit private key
 
 ## Notes
 

bin/cluster

@@ -10,7 +10,7 @@ options = {
 }
 
 OptionParser.new do |opts|
-  opts.banner = "Usage: cluster [-t TAGS] [-l USER] [-k KEY -s SECRET] [-r region]"
+  opts.banner = "Usage: cluster [-t TAGS] [-l USER] [-k KEY -s SECRET] [-r region] [-o SSH_OPTIONS]"
 
   opts.on("-l", "--login [USER]", "Log in with this user") do |opt|
     options['user'] = opt
@@ -32,6 +32,11 @@ OptionParser.new do |opts|
     options['use_public_ip'] = true
   end
 
+  #Allow -o to be passed to give specific ssh options
+  opts.on("-o", "--options [SSH_OPTIONS]", "ssh options to pass directly to cssh") do |opt|
+    options['SSH_OPTIONS'] = opt
+  end
+
 end.parse!
 
 Aws.config.update({:region => options['region']})
@@ -80,6 +85,7 @@ end
 cssh = (/darwin/ =~ RUBY_PLATFORM) ? 'csshX' : 'cssh'
 
 cmd = "#{cssh}"
+cmd = cmd + " --ssh_args '#{options['SSH_OPTIONS']}'"
 cmd = cmd + " -l #{options['user']}" unless options['user'].nil?
 cmd = cmd + " -screen #{options['screen']}" unless options['screen'].nil?
 cmd = cmd + " #{matched_instances.join ' '}"