First you need to install the appropriate version of bundler:

    % gem install bundler -v &#39;~&gt; 1.0.0&#39;
    Successfully installed bundler-1.0.22

Then force rubygems to use the version you want ([see this post](https://stackoverflow.com/questions/4373128/how-do-i-activate-a-different-version-of-a-particular-gem)):

    % bundle _1.0.22_ install

This is what I had to do to get it to work to install with a previous version (2.2.11) of bundler:

    gem install bundler:2.2.11
    bundle _2.2.11_ install

I had the same issue on macOS Mojave. I installed the different version of the bundler gem and uninstall the current version.

`gem install bundler -i &#39;2.0.1&#39;`

`gem uninstall bundler`

Then gives me the option to choose the version to uninstall and I choose the one which is creating the problem.

The error message `In Gemfile: bundler (~&gt; 1.16)` is a bit inaccurate, since the version number requirement can come from other places, such as the `.gemspec` file, which was the case for me:

```ruby
spec.add_development_dependency &quot;bundler&quot;, &quot;~&gt; 1.16&quot;
```

Removing the version number from the `.gemspec` file solved the issue for me:

```ruby
spec.add_development_dependency &quot;bundler&quot;
```

I can&#39;t solve this problem

![enter image description here][1]

  [1]: http://i.stack.imgur.com/Yy1mp.png

I suggest I have to change `c:\Windows\System32\drivers\etc\hosts` file and add after

    # localhost name resolution is handled within DNS itself.

the next line:

    127.0.0.1       mysite.dev

but it doesn&#39;t help. Any suggestions?

Error ocсurrs when I try to open web site project in Microsoft Visual Studio 2012.

Creating a virtual directory failed with the error

How can I get various parameters related to the page request in zf2? Like post/get parameters, the route being accessed, headers sent and files uploaded.

How to access route, post, get etc. parameters in Zend Framework 2

I am in an older Rails project that has a Gemfile. I tried to add a gem to the Gemfile and `bundle install` but got an error:

    Bundler could not find compatible versions for gem &quot;bundler&quot;:
      In Gemfile:
        rails (= 3.0.0) ruby depends on
          bundler (~&gt; 1.0.0) ruby
    
      Current Bundler version:
        bundler (1.1.5)
    
    This Gemfile requires a different version of Bundler.

The version of Rails it&#39;s using requires bundler ~&gt;1.0.0 but I have 1.1.5 installed and am using it for my other projects. Usually I would use `bundle exec ...` but since this is bundler we are talking about, it&#39;s a little more complicated than that. How can I add a gem to my Gemfile and run `bundle install` while using the version of bundler that it requires?


How to `bundle install` when your Gemfile requires an older version of bundler?

I am in an older Rails project that has a Gemfile. I tried to add a gem to the Gemfile and <code>bundle install</code> but got an error:
<pre><code class="hljs language-java">Bundler could not find compatible versions for gem "bundler":
 In Gemfile:
 rails (= 3.0.0) ruby depends on
 bundler (~> 1.0.0) ruby

 Current Bundler version:
 bundler (1.1.5)

This Gemfile requires a different version of Bundler.
</code></pre>
The version of Rails it's using requires bundler ~>1.0.0 but I have 1.1.5 installed and am using it for my other projects. Usually I would use <code>bundle exec ...</code> but since this is bundler we are talking about, it's a little more complicated than that. How can I add a gem to my Gemfile and run <code>bundle install</code> while using the version of bundler that it requires?

I have this code: 

    &lt;%= link_to image_tag(&quot;facebook.png&quot;, :class =&gt; &quot;facebook_icon&quot;, :alt =&gt; &quot;Facebook&quot;, :target =&gt; &quot;_blank&quot;),                 
                &quot;http://www.facebook.com/mypage&quot; %&gt;

How can I make it open in a new tab when a user clicks the link?

Rails: Open link in new tab (with &#39;link_to&#39;)

I have an existing form which is tied to a model named &#39;Order&#39;, but i want to add new form fields that will capture Credit Card info such as name, cc number, etc to be processed on a 3rd party payment gateway.

But since i don&#39;t want to save CC info in our database, there are no corresponding columns of that in my order table. And this gives me an error when submitting the form that those Credit card input fields are not &#39;part&#39; of the order model. 



rails simple_form fields not related to the model

Here are two sample codes.

First one with `collect`:

    User.first.gifts.collect(&amp;:id)

Second one with `pluck`:


    User.first.gifts.pluck(:id)


Is there any difference between them in performance or something else?

What is the difference between pluck and collect in Rails?

I&#39;m using following code to configure logging in my Ruby on Rails application:

environment.rb:

    Rails.logger = Logger.new(STDOUT)
    
    class Logger
      def format_message(severity, timestamp, progname, msg)
      	&quot;#{timestamp.to_formatted_s(:db)} #{severity} #{msg}\n&quot;
      end
    end

I&#39;m trying to set the logging level to warn now using

    config.log_level = :warn

in my production.rb, but it doens&#39;t seem to work. Am I missing something here?

If I put Rails.logger.level = 4 in my environment.rb, it does seem to work. But I would like to configure things in my environment initializers.

Set logging levels in Ruby on Rails

Rails 3.2.1

Is there a way (without [squeel][1]) to use the hash syntax of ActiveRecord to construct a `!=` operator?

Something like `Product.where(id: !params[:id])`

Generates `SELECT products.* FROM products WHERE id != 5`

Looking for the opposite of `Product.where(id: params[:id])`

**UPDATE**

In rails 4 there is a `not` operator.

`Product.where.not(id: params[:id])`


  [1]: https://github.com/activerecord-hackery/squeel

Rails ActiveRecord Query for Not Equal

I&#39;m new to programming. Right now I&#39;m studying Ruby. To my understanding, global variables are defined in the global namespace (so outside of any classes or functions). I&#39;m reading something and it says global variables have a `$` sign before them. What does that mean? Does it mean when I define a function or class and want to reference my global variable (let&#39;s say it is `edmund = 123`) I would have to reference it like this: `$edmund`?

so:

    edmund = 123
    def my_function()
      456 + $edmund
    end


Also are class variables (the ones that begin with `@@`) like instance variables (`@`) where you can access them by calling them through `Class.classvariable`? What is their purpose?

How to reference global variables and class variables?

If an instance variable belongs to a class, can I access the instance variable (e.g. `@hello`) directly using the class instance?

    class Hello
      def method1
        @hello = &quot;pavan&quot;
      end
    end
    
    h = Hello.new
    puts h.method1



Access instance variable from outside the class

    foo ||= []
    foo &lt;&lt; :element

Feels a little clunky. Is there a more idiomatic way?

Create or append to array in Ruby

I did a `bundle show` and get the complete path to a gem directory.

Unfortunately, I removed the directory using `rm -r gem_path`. Then my rails app isn&#39;t working anymore. If I try start server or start rails console it outputs the following error:

&gt; `&lt;class:Application&gt;`: uninitialized constant `MyAPP::Application::Gem` (NameError)

**What should I do to have it back?**

I tried `bundle install` or `bundle update` in hope of forcing the bundle to search the gem and install it back, but didn&#39;t work.

I also tried delete the `Gemfile.lock` and run `bundle install`. Nothing changed, same error.

The gem in question is [**Act as taggable on**][1].


[1]: http://rubygems.org/gems/acts-as-taggable-on

How to reinstall a gem using bundler

I have seen other people with the same issue of [installing RMagick on Mountain Lion](https://stackoverflow.com/questions/11676844/issue-with-installing-imagemagick-and-rmagick-on-mountain-lion) However none of the suggested solutions have allowed me to successfully install rmagick. 

Here is the error message I am getting:

    Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
    checking for Ruby version &gt;= 1.8.5... yes
    checking for /usr/local/bin/gcc-4.2... yes
    checking for Magick-config... yes
    checking for ImageMagick version &gt;= 6.4.9... yes
    checking for HDRI disabled version of ImageMagick... yes
    checking for stdint.h... yes
    checking for sys/types.h... yes
    checking for wand/MagickWand.h... yes
    checking for InitializeMagick() in -lMagickCore... no
    checking for InitializeMagick() in -lMagick... no
    checking for InitializeMagick() in -lMagick++... no
    Can&#39;t install RMagick 2.13.1. Can&#39;t find the ImageMagick library or one of the dependent    libraries. Check the mkmf.log file for more detailed information.

    *** extconf.rb failed ***
    Could not create Makefile due to some reason, probably lack of
    necessary libraries and/or headers.  Check the mkmf.log file for more
    details.  You may need configuration options.

Things I have done:

    Installed XCode
    Installed the command line tools
    Installed XQuartz
    Installed homebrew with imagemagick library
    Installed most recent version of RVM
    Symlinked GCC
    Uninstalled and reinstalled both RVM and imagemagick


Any ideas why I still can&#39;t download rmagick?

Error installing Rmagick on Mountain Lion

I commented out a gem, but &#39;bundle install&#39; still won&#39;t run. How do I find out which gem has a dependency on sys-proctable? 


    $ bundle install
    Fetching gem metadata from https://rubygems.org/.........
    Fetching gem metadata from https://rubygems.org/..
    Resolving dependencies...
    Could not find sys-proctable-0.9.2 in any of the sources
    
    $ grep proctable Gemfile
      #gem &#39;sys-proctable&#39;, &#39;0.9.2&#39;, :path =&gt; &quot;vendor/gems&quot;
    
    $ bundle list
    Resolving dependencies...
    Could not find gem &#39;rspec-rails (= 2.11.0) ruby&#39; in the gems available on this machine.
    
    $ bundle viz
    Resolving dependencies...
    Could not find gem &#39;rspec-rails (= 2.11.0) ruby&#39; in the gems available on this machine.
    
    $ bundle -v
    Bundler version 1.3.0
    
    $ ruby -v
    ruby 1.9.3p385 (2013-02-06 revision 39114) [i386-cygwin]

Gemfile: http://pastebin.com/9WWMfKtv

I&#39;ve already tried these troubleshooting steps: https://github.com/carlhuda/bundler/blob/1-2-stable/ISSUES.md

How do I find out which gem has a specific dependency?

I&#39;m attempting to follow the Hartl Rails Tutorial, and having trouble with the bundler gem.

When using the commands &#39;bundle install&#39; or &#39;bundle update&#39; I get the following output: 

&gt; Fetching source index from https://rubygems.org/
&gt; 
&gt; Could not fetch specs from https://rubygems.org/

I&#39;ve searched for this output, but did not find many related issues online. 

Maybe I have another gem that is interrupting bundler? I have little experience with rails at this point.

        source &#39;https://rubygems.org&#39;
    
    gem &#39;rails&#39;, &#39;3.2.12&#39;
    
    group :development do
      gem &#39;sqlite3&#39;, &#39;1.3.5&#39;
    end
    
    
    # Gems used only for assets and not required
    # in production environments by default.
    group :assets do
      gem &#39;sass-rails&#39;,   &#39;3.2.5&#39;
      gem &#39;coffee-rails&#39;, &#39;3.2.2&#39;
    
      gem &#39;uglifier&#39;, &#39;1.2.3&#39;
    end
    
    gem &#39;jquery-rails&#39;, &#39;2.0.2&#39;


**The solution for me was two parts:** I changed https to http, and that temporarily solved the issue. The second issue was that I think I had a bad install of ruby 2.0.0 even though I was using a fresh install of ruby 1.9.3. So I reinstalled ruby 2.0.0, and I could use bundle install with https.

Bundle Install could not fetch specs from https://rubygems.org/

I am new to Ruby and trying to wrap my head around following concepts: bundler vs RVM vs gems vs RubyGems vs gemsets vs system rub and I&#39;m confused.

Can someone please describe a &#39;best practice&#39; of how I should manage all this on a fresh install of the latest version of Ubuntu? What should I install, and how should I use it all? 

I&#39;m guessing that doing a `sudo apt-get install ruby` is not be recommended, but I am not sure. I tried it on my system in addition to &#39;all the other Ruby stuff&#39;. It&#39;s just adding to my confusion. I am not talking about Rails but just regular Ruby gems (e.g. Vagrant, Chef, scripts).

Content Type	Original Author	Original Content on Stackoverflow
Question	Andrew	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	alexsanford1	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	Kmeixner	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	gsumk	View Answer on Stackoverflow
Solution 4 - Ruby on-Rails	Asbjørn Ulsberg	View Answer on Stackoverflow

How to `bundle install` when your Gemfile requires an older version of bundler?

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

Solution 4 - Ruby on-Rails

How to access route, post, get etc. parameters in Zend Framework 2

Creating a virtual directory failed with the error

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