How to Find Where Gem Files Are Installed

How to find where gem files are installed

Use gem environment to find out about your gem environment:

RubyGems Environment:
  - RUBYGEMS VERSION: 2.1.5
  - RUBY VERSION: 2.0.0 (2013-06-27 patchlevel 247) [x86_64-darwin12.4.0]
  - INSTALLATION DIRECTORY: /Users/ttm/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0
  - RUBY EXECUTABLE: /Users/ttm/.rbenv/versions/2.0.0-p247/bin/ruby
  - EXECUTABLE DIRECTORY: /Users/ttm/.rbenv/versions/2.0.0-p247/bin
  - SPEC CACHE DIRECTORY: /Users/ttm/.gem/specs
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-12
  - GEM PATHS:
     - /Users/ttm/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0
     - /Users/ttm/.gem/ruby/2.0.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /Users/ttm/.rbenv/versions/2.0.0-p247/bin
     - /Users/ttm/.rbenv/libexec
     - /Users/ttm/.rbenv/plugins/ruby-build/bin
     - /Users/ttm/perl5/perlbrew/bin
     - /Users/ttm/perl5/perlbrew/perls/perl-5.18.1/bin
     - /Users/ttm/.pyenv/shims
     - /Users/ttm/.pyenv/bin
     - /Users/ttm/.rbenv/shims
     - /Users/ttm/.rbenv/bin
     - /Users/ttm/bin
     - /usr/local/mysql-5.6.12-osx10.7-x86_64/bin
     - /Users/ttm/libsmi/bin
     - /usr/local/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /usr/local/bin

Notice the two sections for:

• INSTALLATION DIRECTORY
• GEM PATHS

Where do gems install?

Look at your gem environment.

In a terminal run gem env

You should see an entry INSTALLATION DIRECTORY, but there is also GEM PATHS which is where it's loading all your gems from in your current environment.

List of installed gems?

The Gem command is included with Ruby 1.9+ now, and is a standard addition to Ruby pre-1.9.

require 'rubygems'

name = /^/i
dep = Gem::Dependency.new(name, Gem::Requirement.default)
specs = Gem.source_index.search(dep)
puts specs[0..5].map{ |s| "#{s.name} #{s.version}" }
# >> Platform 0.4.0
# >> abstract 1.0.0
# >> actionmailer 3.0.5
# >> actionpack 3.0.5
# >> activemodel 3.0.5
# >> activerecord 3.0.5

---

Here's an updated way to get a list:

require 'rubygems'

def local_gems
   Gem::Specification.sort_by{ |g| [g.name.downcase, g.version] }.group_by{ |g| g.name }
end

Because local_gems relies on group_by, it returns a hash of the gems, where the key is the gem's name, and the value is an array of the gem specifications. The value is an array of the instances of that gem that is installed, sorted by the version number.

That makes it possible to do things like:

my_local_gems = local_gems()

my_local_gems['actionmailer']
# => [Gem::Specification.new do |s|
#       s.authors = ["David Heinemeier Hansson"]
#       s.date = Time.utc(2013, 12, 3)
#       s.dependencies = [Gem::Dependency.new("actionpack",
#         Gem::Requirement.new(["= 4.0.2"]),
#         :runtime),
#        Gem::Dependency.new("mail",
#         Gem::Requirement.new(["~> 2.5.4"]),
#         :runtime)]
#       s.description = "Email on Rails. Compose, deliver, receive, and test emails using the familiar controller/view pattern. First-class support for multipart email and attachments."
#       s.email = "david@loudthinking.com"
#       s.homepage = "http://www.rubyonrails.org"
#       s.licenses = ["MIT"]
#       s.name = "actionmailer"
#       s.require_paths = ["lib"]
#       s.required_ruby_version = Gem::Requirement.new([">= 1.9.3"])
#       s.requirements = ["none"]
#       s.rubygems_version = "2.0.14"
#       s.specification_version = 4
#       s.summary = "Email composition, delivery, and receiving framework (part of Rails)."
#       s.version = Gem::Version.new("4.0.2")
#       end]

And:

puts my_local_gems.map{ |name, specs| 
  [ 
    name,
    specs.map{ |spec| spec.version.to_s }.join(',')
  ].join(' ') 
}
# >> actionmailer 4.0.2
...
# >> arel 4.0.1,5.0.0
...
# >> ZenTest 4.9.5
# >> zucker 13.1

The last example is similar to the gem query --local command-line, only you have access to all the information for a particular gem's specification.

How can I list content of installed gem?

What you're looking for is:

gem contents gem_name_here

Where are Ruby gems located on a server?

Yep. If you deploy on Heroku, you can see bundler doing its work and pulling down the gems.

How to find the path of where a Ruby Gem is installed

According to this ticket, cucumber >= 2.1.0 is not supported yet. You can downgrade, wait for an update, or use their suggested monkey patch:

find in RubyMine folder file named "formatter_03103.rb" and replace
line 22 to

 def initialize(step_mother, path_or_io, options) 

and line 24 to

tc_initialize(options, '|', path_or_io)

And the command gem environment returns lots of info about your gems, including the INSTALLATION DIRECTORY.

How to check if a gem is installed?

General solution

To get the full list of gems that are installed:

gem list

To test for a particular gem, you can use -i with a regex:

gem list -i "^gem_name$"

(Credit to Timo in the comments for this technique.)

Particular solution for OP

If you can't find data_mapper, it may be that the gem name is different from what you expect.

Also, if you're just doing which brew to find brew, you aren't finding the gem called brew, you're finding the location of the brew executable. Try gem which brew instead.

EDIT:

If you're looking for data_mapper by doing which data_mapper, you probably won't find it. which is a unix program for finding unix executables, and data_mapper probably doesn't have one.

Since your goal is to verify a gem is installed with the correct version, use gem list. You can limit to the specific gem by using gem list data_mapper.

To verify that it's installed and working, you'll have to try to require the gem and then use it in your code.

How can I see files inside a Ruby .gem?

with gem unpack

You can use the gem unpack command to extract the contents of a .gem file into a directory. Assuming you have some_file.gem:

gem unpack some_file.gem

with tar

If you want to list the gem's contents without unpacking it, you can use tar (a .gem file is just a .tar file with a specific format).

tar --to-stdout -xf some_file.gem data.tar.gz | tar -zt

Here's a longer explanation of how this works:

# Download a .gem file
$ gem fetch json_pure -v '2.0.3'
Fetching: json_pure-2.0.3.gem (100%)
Downloaded json_pure-2.0.3

# List the contents of the gem
# You can see that it contains separate files for metadata, the gem files, and a checksum
$ tar -tf json_pure-2.0.3.gem
metadata.gz
data.tar.gz
checksums.yaml.gz

# Extract just the data.tar.gz file, then unzip and list the contents of *that* file.
#   --to-stdout so we can pipe it to another command
#   -x extract
#   -f file
#
# Then:
#   -z use gunzip to decompress the .tar.gz file
#   -t list the contents of the archive
tar --to-stdout -xf json_pure-2.0.3.gem data.tar.gz | tar -zt
./tests/test_helper.rb
.gitignore
.travis.yml
CHANGES.md
Gemfile
...

In most cases gem unpack is probably what you want. The main benefit to the tar command above is that it doesn't create any new directories or actually unpack the files. It might also be useful if you don't have rubygems installed.

Where does bundler store gems?

It depends. In the usual development setup they are installed where they would be when you install a gem "normally" (by running gem install foo) and bundler won't reinstall gems that are already there. This location depends on how rubygems itself is configured.

If you run bundle install with the --deployment option then the gems will be installed in a location unique to your app (you can pass this as a separate option but it defaults to vendor/bundle)

You can also run bundle package to store all the .gem files your app uses in vendor/cache. Running bundle install will prefer gems in vendor/cache to gems in other locations.

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