Getting started with rubygems

Remarks#

Gems can be used to extend or modify functionality in Ruby applications. Commonly they’re used to distribute reusable functionality that is shared with other Rubyists for use in their applications and libraries. Some gems provide command line utilities to help automate tasks and speed up your work.

The RubyGems software allows you to easily download, install and use Ruby software packages on your system. The software package is called a gem and contains a packaged Ruby application or library.

Installation or Setup

If you don’t have any RubyGems installed, there is still the pre-gem approach to getting software, doing it manually:

Download from RubyGems
Unpack into a directory and cd there
Install with: ruby setup.rb (you may need admin/root privilege)
```
sudo ruby setup.rb
```

For more details and other options, see:

ruby setup.rb --help

Installation on Linux

Make sure you have ruby installed before installing rubygems, and then:

Installing RubyGems Using apt-get on Ubuntu

sudo apt-get install rubygems

Installing RubyGems Using yum

sudo yum install rubygems

Manual Installation Method

wget https://rubygems.org/rubygems/rubygems-2.6.6.tgz
tar xvf rubygems-2.6.6.tgz
cd rubygems-2.6.6
sudo ruby setup.rb

Install specific precompiled ruby version and ruby gems (Ubuntu)

sudo apt-add-repository ppa:brightbox/ruby-ng

Hit Enter to confirm

sudo apt-get update

Then you can install your ruby version of choice (the ppa supports ruby2.0 ruby2.1 ruby2.2 ruby2.3 and legacy versions ruby1.8 ruby1.9.1) Don’t forget to include the respective -dev package for your version. Otherwise the development of native extensions such as Nokogiri or mysql2 will fail.

sudo apt-get install ruby2.3 ruby2.3-dev ruby-switch

sudo ruby-switch set ruby2.3

ruby -v

>> ruby 2.3.1p112 (2016-04-26) [x86_64-linux-gnu]

Now you can install any desired gem systemwide for all users via sudo gem install gemname.

Note:

This method installs and sets ruby and rubygems system-wide for all users
Requires sudo to install gems (sudo gem install rails) but don’t run bundle as root. If it needs to install gems it will ask for the sudo password.

Change gem source

# list gem sources:
gem sources -l
# remove default gem source:
gem sources -r https://rubygems.org/
# add other gem sources:
gem sources -a https://ruby.taobao.org/