In Capistrano v3, you must specify where you want to run the code by calling `on` with a list of hostnames, e.g.

    task :execute_on_server do
      on &quot;root@example.com&quot; do
        execute &quot;some_command&quot;
      end
    end

If you have roles set up, you can use the `roles` method as a convenience:

    role :mailserver, &quot;root@mail.example.com&quot;

    task :check_mail do
      on roles(:mailserver) do
        execute &quot;some_command&quot;
      end
    end

There is some v3 documentation here: http://www.capistranorb.com/

I was playing with python and I realized we don&#39;t need to use &#39;+&#39; operator to concatenate static strings. But it fails if I assign it to a variable. 

For example:

    string1 = &#39;Hello&#39;   &#39;World&#39;  #1 works fine
    string2 = &#39;Hello&#39; + &#39;World&#39;  #2 also works fine
    
    string3 = &#39;Hello&#39;
    string4 = &#39;World&#39;
    string5 = string3   string4  #3 causes syntax error
    string6 = string3 + string4  #4 works fine

Now I have two questions:

1. Why statement 3 does not work while statement 1 does? 
2. Is there any technical difference such as calculation speed etc. between statement 1 and 2?


String concatenation without &#39;+&#39; operator

I am trying to replicate  what you can see here in this image. ![enter image description here][1]


  [1]: http://i.stack.imgur.com/9NB1w.png

I want to be able to either type in the text field above the box or just click on the option directly.

What would be the best way to go about that? Is there anything bootstrap related that exists already?

Creating a select box with a search option

I&#39;m new to Capistrano and I&#39;ve tried using Capistrano&#39;s DSL to run shell commands on the server (&#39;run&#39;, &#39;execute&#39;, etc.), but it appears that it was deprecated. After searching and searching for a functional equivalent, I still am lost.

Current code:

    desc &#39;Do something&#39;
    task :do_something
      execute &#39;echo sometext&#39;
    end

Output:

        cap aborted!
        undefined method `execute&#39; for main:Object
        /Users/Justin/Dropbox/xxxx/xxxx/xxxx/Capfile:45:in `block (2 levels) in &lt;top (required)&gt;&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/lib/capistrano/application.rb:12:in `run&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/bin/cap:3:in `&lt;top (required)&gt;&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `load&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `&lt;main&gt;&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `eval&#39;
        /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `&lt;main&gt;&#39;
        Tasks: TOP =&gt; deploy:do_something


How to run shell commands on server in Capistrano v3?

I'm new to Capistrano and I've tried using Capistrano's DSL to run shell commands on the server ('run', 'execute', etc.), but it appears that it was deprecated. After searching and searching for a functional equivalent, I still am lost.
Current code:
<pre><code class="hljs language-sql">desc 'Do something'
task :do_something
 execute 'echo sometext'
end
</code></pre>
Output:
<pre><code class="hljs language-bash"> cap aborted!
 undefined method `execute' for main:Object
 /Users/Justin/Dropbox/xxxx/xxxx/xxxx/Capfile:45:in `block (2 levels) in &#x3C;top (required)>'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/lib/capistrano/application.rb:12:in `run'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/bin/cap:3:in `&#x3C;top (required)>'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `load'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `&#x3C;main>'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `eval'
 /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `&#x3C;main>'
 Tasks: TOP => deploy:do_something
</code></pre>

I have a data structure in the following format:

    data_hash = [
        { price: 1, count: 3 },
        { price: 2, count: 3 },
        { price: 3, count: 3 }
      ]

Is there an efficient way to get the values of `:price` as an array like `[1,2,3]`?

Collect values from an array of hashes

If I have an array of strings e.g.

    a = [&#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;]

and I want to output the elements, to a file (e.g. .txt) one per line. So far I have:

    File.new(&quot;test.txt&quot;, &quot;w+&quot;)
    File.open(&quot;test.txt&quot;, &quot;w+&quot;) do |i|
	    i.write(a)
    end

This gives me the array on one line of the test.txt file.
How can I iterate over the array, adding each value to a new line of the file?

Add each array element to the lines of a file in ruby

I&#39;m new to ruby. I tried to install Ruby Gems on my PC by following the steps given in the site http://rubygems.org/pages/download.

I downloaded the package from the mentioned site, changed the directory to the directory in which the setup resides, and tried to run setup using the command `setup.rb` in command prompt.

But I get a window pop up that says &quot;Windows can&#39;t open this file&quot; and prompts me to select a program to open this file.

What should I do now? Let me know if I am doing something wrong.


Installing RubyGems in Windows

I was evaluating **Slim** as a replacement for **HAML** in a personal project, and it doesn&#39;t appear to handle HTML5 data attributes as gracefully as HAML. I was hoping someone may have also run into this, or may have known about an option/syntax I haven&#39;t yet found in their docs.

HAML allows you to define [HTML 5 data attributes][1] simply by using nested hashes like so: 

`%a{data: {key1: &#39;val&#39;, key2: &#39;val&#39;}}`

resulting in

`&lt;a data-key1=&#39;val&#39; data-key2=&#39;val&#39;&gt;&lt;/a&gt;`

  [1]: http://haml.info/docs/yardoc/file.REFERENCE.html#html5_custom_data_attributes

Best way to handle data attributes in Slim

 I have installed the RailsTutorial sample app(the twitter like application) and am trying to understand why the following piece of console code does not update the database when I try updating the user db. I am expecting the user information to get updated once I use the `user.save`. However, this rolls back to unedited data. Is this due to a user based restriction? 

Users controller:

    class UsersController &lt; ApplicationController

    #before_filter :signed_in_user, only: [:index, :edit, :update, :destroy, :following, :followers]
    # By default before filters apply to all actions
    #before_filter :correct_user, only: [:edit, :update]
      def edit
	    @user = User.find(params[:id])
      end
    
      def update
    
        @user = User.find params[:id]
    
        respond_to do |format|
        
        if @user.update_attributes(params[:user])
          flash[:notice] = &quot;Profile updated&quot;
          format.html { redirect_to(@user, :notice =&gt; &#39;User was successfully updated.&#39;) }
          format.json { respond_with_bip(@user) }
        else
        
          format.html { render :action =&gt; &quot;edit&quot; }
          format.json { respond_with_bip(@user) }
        end
        end
     end

      private
  	

	  def correct_user
		@user = User.find(params[:id])
		redirect_to(root_path) unless current_user?(@user)
	  end

	  def admin_user
		redirect_to(root_path) unless current_user.admin?
	  end
 

    end


Rails console:
  

    1.9.3-p392 :001 &gt; user = User.find(109)

  
    User Load (8.2ms)  SELECT &quot;users&quot;.* FROM &quot;users&quot; WHERE &quot;users&quot;.&quot;id&quot; = ? LIMIT 1  [[&quot;id&quot;, 109]]
     =&gt; #&lt;User id: 109, name: &quot;laurie&quot;, email: &quot;auriepage@gmail.com&quot;, created_at: &quot;2013-09-26 18:10:12&quot;, updated_at: &quot;2013-09-26 18:10:12&quot;, password_digest: &quot;$2a$10$aXEtun8Z2Deqy2wNxvFRNOjPczKQkYc1vDezP5OduJuF...&quot;, remember_token: &quot;YhIUhgFm9iMewxdNOHJ45A&quot;, admin: false&gt; 

    1.9.3-p392 :002 &gt; user.name = &quot;larry&quot;
     =&gt; &quot;larry&quot; 

    1.9.3-p392 :003 &gt; user.save
       (0.2ms)  begin transaction
      User Exists (0.6ms)  SELECT 1 AS one FROM &quot;users&quot; WHERE (LOWER(&quot;users&quot;.&quot;email&quot;) = LOWER(&#39;auriepage@gmail.com&#39;) AND &quot;users&quot;.&quot;id&quot; != 109) LIMIT 1
       (0.1ms)  rollback transaction
     =&gt; false 

User model:

    class User &lt; ActiveRecord::Base

    # Declaration of public variables	
      attr_accessible :email, :name, :password, :password_confirmation
      has_secure_password
      has_many :microposts, dependent: :destroy
      has_many :relationships, foreign_key: &quot;follower_id&quot;, dependent: :destroy
      has_many :followed_users, through: :relationships, source: :followed
      has_many :reverse_relationships, foreign_key: &quot;followed_id&quot;, class_name: &quot;Relationship&quot;, dependent: :destroy
      has_many :followers, through: :reverse_relationships, source: :follower
    
      before_save {email.downcase!}
      before_save :create_remember_token
    
      validates :name, presence: true, length: {maximum: 50}
      VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
      validates :email, presence: true, format: {with: VALID_EMAIL_REGEX}, uniqueness: {case_sensitive: false}
      validates :password, presence: true, length: {minimum: 6}
      validates :password_confirmation, presence: true
      after_validation {self.errors.messages.delete(:password_digest)}

     private
      	def create_remember_token
    		self.remember_token = SecureRandom.urlsafe_base64
    	end
    end


Why does my rails rollback when I try to user.save?

     INFO [050fe961] Running mkdir -p /home/rails/rails-
    capistrano/releases/20140114234157 on staging-rails
    DEBUG [050fe961] Command: cd /home/rails/rails-capistrano/repo &amp;&amp; ( PATH=/opt/ruby/bin:$PATH GIT_ASKPASS=/bin/echo GIT_SSH=/tmp/rails/git-ssh.sh mkdir -p /home/rails/rails-capistrano/releases/20140114234157 )
     INFO [050fe961] Finished in 0.142 seconds with exit status 0 (successful).
     INFO [2dea2fe5] Running git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157 on staging-rails
    DEBUG [2dea2fe5] Command: cd /home/rails/rails-capistrano/repo &amp;&amp; ( PATH=/opt/ruby/bin:$PATH GIT_ASKPASS=/bin/echo GIT_SSH=/tmp/rails/git-ssh.sh git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157 )
    DEBUG [2dea2fe5] 	fatal: Not a valid object name
    DEBUG [2dea2fe5] 	tar: This does not look like a tar archive
    DEBUG [2dea2fe5] 	tar: 
    DEBUG [2dea2fe5] 	Exiting with failure status due to previous errors      

I am confused about two things:

 1. Why is Capistrano running `git archive` here:&lt;br&gt;
`git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157`

 2. Why is `tar` failing?

Capistrano error tar: This does not look like a tar archive

I&#39;ve switched to using [environment variables for configuration](http://12factor.net/config) and it works very well - except when I have to deploy or run tasks with capistrano.

Capistrano 3 seems to execute each command prefixed with `/usr/bin/env` which erases any environment variables I&#39;ve set through `.bashrc`.

*EDIT* - on doing some more reasearch, this might not be the issue, the issue might be because capistrano executes as a non-login, non-interactive shell and does not load `.bashrc` or `.bash_profile`. Still stuck, though.

What would be the best way of making sure the environment vars are set when capistrano executes its tasks?

Capistrano and environment variables

I&#39;m using Rails, Puma, Capistrano3. I have installed the gem `capistrano3-puma` as well. I started Puma with Puma Jungle [https://github.com/puma/puma/tree/master/tools/jungle/upstart][1]

How do I restart Puma during deployment?

  [1]: https://github.com/puma/puma/tree/master/tools/jungle/upstart

Content Type	Original Author	Original Content on Stackoverflow
Question	Jgod	View Question on Stackoverflow
Solution 1 - Ruby	lmars	View Answer on Stackoverflow

How to run shell commands on server in Capistrano v3?

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

Creating a select box with a search option

String concatenation without '+' operator

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