gem error collection

Updated at: February 23, 2017

can’t require installed gems with this kind of error msg “`require’: no such file xxxx”

1. use –user-install option to install gem into your home dir in case you don’t have root permission

gem install xxx --user-install

#add below to your corresponding profile/rc file e.g. .bashrc/.kshrc/.profile
if which ruby >/dev/null && which gem >/dev/null; then
    PATH="$(ruby -rubygems -e 'puts Gem.user_dir')/bin:$PATH"

2. if you are using ruby >=1.9, directly add “require ‘xxx’” at head.

since ruby1.9, ‘require “rubygems”‘ happens automatically

if you are using ruby<1.9, add “require ‘rubygems’” at top of head

what does “require ‘rubygems’ do?

  • When RubyGems is required, Kernel#require is replaced with our own which is capable of loading gems on demand.
  • When you call require ‘x’, this is what happens:
  • If the file can be loaded from the existing Ruby loadpath, it is.
  • Otherwise, installed gems are searched for a file that matches. If it’s found in gem ‘y’, that gem is activated (added to the loadpath).
  • The normal require functionality of returning false if that file has already been loaded is preserved.