title: Uninstalling Ruby gems
body: <pre><code>user@machine:~$ gem list
  
  *** 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)
  sass (3.4.23)
  test-unit (3.1.7)
  user@machine:~$ sudo gem uninstall rake
  ERROR:  While executing gem ... (Gem::InstallError)
      rake is not installed in GEM_HOME, try:
      gem uninstall -i /usr/share/rubygems-integration/all rake
  user@machine:~$ sudo gem uninstall -i /usr/share/rubygems-integration/all rake 
  Remove executables:
      rake
  
  in addition to the gem? [Yn]  Y
  ERROR:  While executing gem ... (Gem::FilePermissionError)
      You don't have write permissions for the /usr/share/rubygems-integration/all/bin directory.
  user@machine:~$ ls /usr/share/rubygems-integration/all/
  specifications
  user@machine:~$ 
  </code></pre>
  
  <p>I can not uninstall this gem in particular, neither use it :(
  If seems that it doesn't exist. </p>
  
  <p>My ruby verison is 2.3.1.p112</p>