Introduction
Ruby has become a popular and powerful programming language over the years since its inception in 1995.
The Ruby programming language is the foundation for the popular web development framework Ruby on Rails.
Increased popularity implied increased user base and increased functionality. So, ruby packages or gems were introduced to add additional features to the installed ruby programming language. In this article, we will explain how to install and use RubyGems – a sophisticated package manager for Ruby.
Install RubyGems
Ruby does not come installed on Linux systems out of the box.
When you install RubyGems, it will install ruby as well as a required pre-requisite.
Install rubygems on ubuntu:
The ruby language packages, as well as the rubygems package, are available in the online repositories so you may type apt install rubgems to install them as shown below:
root@linuxnix:~# apt install rubygems Reading package lists... Done Building dependency tree Reading state information... Done Note, selecting 'ruby' instead of 'rubygems' The following additional packages will be installed: libruby2.3 rake ruby2.3 Suggested packages: ri ruby-dev The following NEW packages will be installed: libruby2.3 rake ruby ruby2.3 0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded. Need to get 3,053 kB of archives. After this operation, 14.0 MB of additional disk space will be used. Do you want to continue? [Y/n] Y Get:1 http://ap-southeast-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libruby2.3 amd64 2.3.1-2~16.04.2 [2,958 kB] Get:2 http://ap-southeast-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 ruby2.3 amd64 2.3.1-2~16.04.2 [41.0 kB] Get:3 http://ap-southeast-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 ruby all 1:2.3.0+1 [5,530 B] Get:4 http://ap-southeast-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 rake all 10.5.0-2 [48.2 kB] Fetched 3,053 kB in 0s (49.9 MB/s) Selecting previously unselected package libruby2.3:amd64. (Reading database ... 108520 files and directories currently installed.) Preparing to unpack .../libruby2.3_2.3.1-2~16.04.2_amd64.deb ... Unpacking libruby2.3:amd64 (2.3.1-2~16.04.2) ... Selecting previously unselected package ruby2.3. Preparing to unpack .../ruby2.3_2.3.1-2~16.04.2_amd64.deb ... Unpacking ruby2.3 (2.3.1-2~16.04.2) ... Selecting previously unselected package ruby. Preparing to unpack .../ruby_1%3a2.3.0+1_all.deb ... Unpacking ruby (1:2.3.0+1) ... Selecting previously unselected package rake. Preparing to unpack .../archives/rake_10.5.0-2_all.deb ... Unpacking rake (10.5.0-2) ... Processing triggers for libc-bin (2.23-0ubuntu9) ... Processing triggers for man-db (2.7.5-1) ... Setting up libruby2.3:amd64 (2.3.1-2~16.04.2) ... Setting up ruby2.3 (2.3.1-2~16.04.2) ... Setting up ruby (1:2.3.0+1) ... Setting up rake (10.5.0-2) ... Processing triggers for libc-bin (2.23-0ubuntu9) ... root@linuxnix:~#
Install rubygems on Centos:
Ruby is not installed on Centos by default but is available in the base repository.
To install ruby and rubygems in Centos, type yum install rubygems as shown below:
[root@linuxnix~]# yum install rubygems Loaded plugins: fastestmirror, langpacks base | 3.6 kB 00:00:00 epel/x86_64/metalink | 7.0 kB 00:00:00 extras | 3.4 kB 00:00:00 puppetlabs-pc1 | 2.5 kB 00:00:00 updates | 3.4 kB 00:00:00 Loading mirror speeds from cached hostfile * base: centos.mirror.net.in * epel: epel.mirror.angkasa.id * extras: mirror.digistar.vn * updates: mirrors.123host.vn Resolving Dependencies --> Running transaction check ---> Package rubygems.noarch 0:2.0.14.1-30.el7 will be installed --> Processing Dependency: rubygem(rdoc) >= 4.0.0 for package: rubygems-2.0.14.1-30.el7.noarch --> Processing Dependency: rubygem(psych) >= 2.0.0 for package: rubygems-2.0.14.1-30.el7.noarch --> Processing Dependency: rubygem(io-console) >= 0.4.2 for package: rubygems-2.0.14.1-30.el7.noarch --> Processing Dependency: ruby(release) for package: rubygems-2.0.14.1-30.el7.noarch --> Processing Dependency: /usr/bin/ruby for package: rubygems-2.0.14.1-30.el7.noarch --> Running transaction check ---> Package ruby.x86_64 0:2.0.0.648-30.el7 will be installed --> Processing Dependency: rubygem(bigdecimal) >= 1.2.0 for package: ruby-2.0.0.648-30.el7.x86_64 ---> Package ruby-libs.x86_64 0:2.0.0.648-30.el7 will be installed ---> Package rubygem-io-console.x86_64 0:0.4.2-30.el7 will be installed ---> Package rubygem-psych.x86_64 0:2.0.0-30.el7 will be installed ---> Package rubygem-rdoc.noarch 0:4.0.0-30.el7 will be installed --> Processing Dependency: ruby(irb) = 2.0.0.648 for package: rubygem-rdoc-4.0.0-30.el7.noarch --> Processing Dependency: rubygem(json) >= 1.7.7 for package: rubygem-rdoc-4.0.0-30.el7.noarch --> Running transaction check ---> Package ruby-irb.noarch 0:2.0.0.648-30.el7 will be installed ---> Package rubygem-bigdecimal.x86_64 0:1.2.0-30.el7 will be installed ---> Package rubygem-json.x86_64 0:1.7.7-30.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: rubygems noarch 2.0.14.1-30.el7 base 216 k Installing for dependencies: ruby x86_64 2.0.0.648-30.el7 base 69 k ruby-irb noarch 2.0.0.648-30.el7 base 90 k ruby-libs x86_64 2.0.0.648-30.el7 base 2.8 M rubygem-bigdecimal x86_64 1.2.0-30.el7 base 81 k rubygem-io-console x86_64 0.4.2-30.el7 base 52 k rubygem-json x86_64 1.7.7-30.el7 base 77 k rubygem-psych x86_64 2.0.0-30.el7 base 79 k rubygem-rdoc noarch 4.0.0-30.el7 base 319 k Transaction Summary ================================================================================ Install 1 Package (+8 Dependent packages) --------------------------------------------------------output truncated for brevity Installed: rubygems.noarch 0:2.0.14.1-30.el7 Dependency Installed: ruby.x86_64 0:2.0.0.648-30.el7 ruby-irb.noarch 0:2.0.0.648-30.el7 ruby-libs.x86_64 0:2.0.0.648-30.el7 rubygem-bigdecimal.x86_64 0:1.2.0-30.el7 rubygem-io-console.x86_64 0:0.4.2-30.el7 rubygem-json.x86_64 0:1.7.7-30.el7 rubygem-psych.x86_64 0:2.0.0-30.el7 rubygem-rdoc.noarch 0:4.0.0-30.el7 Complete! [root@linuxnix~]#
Now that we have seen how to install rubygems, we’ll go through some usage examples.
I’ll be using an Ubuntu 16.04 system for the demonstrations ahead.
Example 1: Verify that ruby and rubygems have been installed
To check the version of ruby and rubygems on the system, we use the ruby –version and gem –version commands respectively.
root@linuxnix:~# ruby --version ruby 2.3.1p112 (2016-04-26) [x86_64-linux-gnu] root@linuxnix:~# gem --version 2.5.1
Example 2: Check that gem environment is set up
To verify that the environment for rubygems is set up correctly, we use the gem env command as shown below.
root@linuxnix:~# gem env RubyGems Environment: - RUBYGEMS VERSION: 2.5.1 - RUBY VERSION: 2.3.1 (2016-04-26 patchlevel 112) [x86_64-linux-gnu] - INSTALLATION DIRECTORY: /var/lib/gems/2.3.0 - USER INSTALLATION DIRECTORY: /root/.gem/ruby/2.3.0 - RUBY EXECUTABLE: /usr/bin/ruby2.3 - EXECUTABLE DIRECTORY: /usr/local/bin - SPEC CACHE DIRECTORY: /root/.gem/specs - SYSTEM CONFIGURATION DIRECTORY: /etc - RUBYGEMS PLATFORMS: - ruby - x86_64-linux - GEM PATHS: - /var/lib/gems/2.3.0 - /root/.gem/ruby/2.3.0 - /usr/lib/x86_64-linux-gnu/rubygems-integration/2.3.0 - /usr/share/rubygems-integration/2.3.0 - /usr/share/rubygems-integration/all - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :backtrace => false - :bulk_threshold => 1000 - REMOTE SOURCES: - https://rubygems.org/ - SHELL PATH: - /usr/local/sbin - /usr/local/bin - /usr/sbin - /usr/bin - /sbin - /bin - /snap/bin
Example 3: List installed gems
To list currently installed ruby gems or packages we use the following command
root@linuxnix:~# gem list --local *** LOCAL GEMS *** bigdecimal (1.2.8) did_you_mean (1.0.0) io-console (0.4.5) json (1.8.3) minitest (5.8.4) net-telnet (0.1.1) power_assert (0.2.7) psych (2.0.17) rake (10.5.0) rdoc (4.2.1) test-unit (3.1.7) root@linuxnix:~#
Example 4: Search for gems
To look for ruby gems we use the gem search command followed by the named of the package we wish to search for.
Let’s demonstrate by searching for Huginn, a system for building agents that perform automated tasks for you online
root@linuxnix:~# gem search huginn *** REMOTE GEMS *** huginn_agent (0.6.1) huginn_github_notifications_agent (0.0.1) huginn_naive_bayes_agent (0.1.4) huginn_s3_file_agent (0.1.1) huginn_slackbot_agent (0.1) huginn_todoist_agent (0.5.0) huginn_transmission_agent (0.1) huginn_xero_agent (0.1.1)
Example 5: Install a ruby gem
We use the gem install command to install a ruby gem.
Let’s install the huginn gem we searched for earlier.
root@linuxnix:~# gem install huginn_agent Fetching: thor-0.20.0.gem (100%) Successfully installed thor-0.20.0 Fetching: huginn_agent-0.6.1.gem (100%) Successfully installed huginn_agent-0.6.1 Parsing documentation for thor-0.20.0 Installing ri documentation for thor-0.20.0 Parsing documentation for huginn_agent-0.6.1 Installing ri documentation for huginn_agent-0.6.1 Done installing documentation for thor, huginn_agent after 1 seconds 2 gems installed
Example 6: Remove a gem
We use the gem uninstall command to remove a ruby gem.
Let’s uninstall the huginn gem we searched for earlier.
root@linuxnix:~# gem uninstall huginn_agent Remove executables: huginn_agent in addition to the gem? [Yn] y Removing huginn_agent Successfully uninstalled huginn_agent-0.6.1 root@linuxnix:~#
Example 7: Update ruby gems
To update all currently installed ruby gems on the system, use the gem updated command as shown below
root@linuxnix:~# gem update Updating installed gems ---------output truncated for brevity Done installing documentation for test-unit after 1 seconds Gems updated: bigdecimal did_you_mean io-console json minitest power_assert psych rake rdoc test-unit root@linuxnix:~#
Example 8: List files that make up a ruby gem
To view files installed when we install a ruby gem, use the gem contents command.
Here is an example:
root@linuxnix:~# gem contents json /usr/lib/ruby/2.3.0/json.rb /usr/lib/ruby/2.3.0/json/add/bigdecimal.rb /usr/lib/ruby/2.3.0/json/add/complex.rb /usr/lib/ruby/2.3.0/json/add/core.rb /usr/lib/ruby/2.3.0/json/add/date.rb /usr/lib/ruby/2.3.0/json/add/date_time.rb /usr/lib/ruby/2.3.0/json/add/exception.rb /usr/lib/ruby/2.3.0/json/add/ostruct.rb /usr/lib/ruby/2.3.0/json/add/range.rb /usr/lib/ruby/2.3.0/json/add/rational.rb /usr/lib/ruby/2.3.0/json/add/regexp.rb /usr/lib/ruby/2.3.0/json/add/struct.rb /usr/lib/ruby/2.3.0/json/add/symbol.rb /usr/lib/ruby/2.3.0/json/add/time.rb /usr/lib/ruby/2.3.0/json/common.rb /usr/lib/ruby/2.3.0/json/ext.rb /usr/lib/ruby/2.3.0/json/generic_object.rb /usr/lib/ruby/2.3.0/json/version.rb /usr/lib/x86_64-linux-gnu/ruby/2.3.0/json/ext/generator.so /usr/lib/x86_64-linux-gnu/ruby/2.3.0/json/ext/parser.so
Conclusion
This concludes our demonstration of using the rubygems tool for interacting with Ruby packages in Linux. We will try to post more articles on ruby in the future.
Sahil Suri
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