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A utility for producing a list of classes/modules with version info, that are present in an application, gem, or ruby program file.


The vls gem is normally used as a stand-alone utility. However, its functionality may be added to any Ruby application. To do so you can add this line to your application's Gemfile:

gem 'vls'

And then execute:

$ bundle

Far more likely however, install it yourself as:

$ gem install vls

The vls gem itself is found at: ( )


The vls utility is normally used at the command line. The usage template is:

vls (VersionLS): 0.3.6

A command line utility that lists the versions of modules used by the specified
gems/ruby files.

Usage: $ vls <options> <names>

  --filter, -f <s/r> = Filter results by string or regular expression.
  --help, -h, -?     = Display this text and exit.
  --raw,  -r         = Display results with no header text.

<names> are gems/files to be required before modules are listed.

 To specify a file instead of a gem, a '.rb' extension is required.

For example:

$ vls rails
vls (VersionLS): 0.3.6

ActionPack, 4.2.6
ActiveSupport, 4.2.6
ActiveSupport::Logger, 1.2.7
Gem, 2.2.2
I18n, 0.7.0
JSON, 1.8.3
Logger, 1.2.7
OpenSSL, 1.1.0
Psych, 2.0.5
Rack, [1, 3]
Rails, 4.2.6
ThreadSafe, 0.3.5

In order to use relative paths instead of the gem search path, the .rb extension needs to be specified on the target file.

$ vls ruby_sscanf.rb
vls (VersionLS): 0.3.6

FormatEngine, 0.7.2
Gem, 2.2.2
RubySscanf, 0.2.3

The vls utility is also available for use within an application. It may be accessed with:

module_version_list = VersionLS.vls(filter=/./)

This returns an array of entries, sorted by module name, consisting of an array with the module and a string with its version. Also, the Object class is monkey patched with the vls method that outputs the information to the console.


Note that these methods do not accept a list of modules to be required. It is assumed that when embedded within an application, the needed facilities would have already been loaded. In addition, the vls listing to the console has no header information. If this is desired, the application should do a puts of the appropriate descriptive text.

Both of these methods do take an optional filter string or regular expression.

The Rails Console

If the vls gem has been added to a rails project (in its Gemfile), its functionality is also easily accessed via the rails console:

$ rails console

followed by


will create a formatted listing of the modules with version info of the module load out of the web site. For example:

$ rails console
Loading development environment (Rails 4.2.6)
irb(main):001:0> vls
ActionDispatch::Journey::Router, 2.0.0
ActionMailer, 4.2.6
ActionPack, 4.2.6
ActionView, 4.2.6
ActiveJob, 4.2.6
ActiveModel, 4.2.6
ActiveRecord, 4.2.6
ActiveSupport, 4.2.6
ActiveSupport::Logger, 1.2.7
Arel, 6.0.3
Bundler, 1.11.2
Coffee::Rails, 4.1.1
Concurrent, 1.0.1
Erubis, 2.7.0
ExecJS, 2.6.0
Gem, 2.2.2
I18n, 0.7.0
IRB::ReadlineInputMethod, 5.2
JSON, 1.8.3
Jquery::Rails, 4.1.1
Logger, 1.2.7
Loofah, 2.0.3
MIME::Type, 2.99.1
MIME::Types, 2.99.1
MIME::Types::WarnLogger, 1.2.7
Mail, 2.6.3
MultiJson, 1.11.2
OpenSSL, 1.1.0
PG, 0.18.4
Psych, 2.0.5
Rack, 1.3
Rack::Test, 0.6.3
Rails, 4.2.6
Rails::Html::FullSanitizer, 1.0.3
Rails::Html::LinkSanitizer, 1.0.3
Rails::Html::Sanitizer, 1.0.3
Rails::Html::WhiteListSanitizer, 1.0.3
Readline, 5.2
Sass, 3.4.21 (Selective Steve)
Sass::Rails, 5.0.4
Sprockets, 3.5.2
Sprockets::Cache, 3.0
Sprockets::ClosureCompressor, 1
Sprockets::CoffeeScriptProcessor, 1
Sprockets::DirectiveProcessor, 1
Sprockets::EcoProcessor, 1
Sprockets::EjsProcessor, 1
Sprockets::Rails, 3.0.4
Sprockets::SassCompressor, 1
Sprockets::UglifierCompressor, 1
Sprockets::YUICompressor, 1
TZInfo::Data, 1.2016.2
ThreadSafe, 0.3.5
Tilt, 2.0.2
Turbolinks, 2.5.3
URI, 0.9.11
URI::FTP, 0.9.11
URI::GID, 0.9.11
URI::Generic, 0.9.11
URI::HTTP, 0.9.11
URI::HTTPS, 0.9.11
URI::LDAP, 0.9.11
URI::LDAPS, 0.9.11
URI::MailTo, 0.9.11
Uglifier, 2.7.2
Zlib, 0.6.0
=> nil

Of course, filtering is available at this level too:

irb(main):003:0> vls 'Rails'
Coffee::Rails, 4.1.1
Jquery::Rails, 4.1.1
Rails, 4.2.6
Rails::Html::FullSanitizer, 1.0.3
Rails::Html::LinkSanitizer, 1.0.3
Rails::Html::Sanitizer, 1.0.3
Rails::Html::WhiteListSanitizer, 1.0.3
Sass::Rails, 5.0.4
Sprockets::Rails, 3.0.4

Usage in Rails Views

It is also possible to incorporate vls data into a view using the VersionLS.vls method in a controller and passing the resultant array of data to a view for rendering in a web page. This may be useful for a diagnostic or informational page in a web site. However, a detailed examination of this task is beyond the scope of this document and readers are advised to consult Ruby on Rails tutorials for more information.


Plan A

  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request

Plan B

Go to the GitHub repository and raise an issue calling attention to some aspect that could use some TLC or a suggestion or an idea.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the fully_freeze project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.


The version ls utility; List the modules of a gem/application with version info. Useful for determining application composition. Great debug tool in rails console.





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