Ruby – How to install a gem or update RubyGems if it fails with a permissions error

macosrubyrubygems

I'm trying to install a gem using gem install mygem or update RubyGems using gem update --system, and it fails with this error:

ERROR:  While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.

Does anyone have an idea how to solve this?

Try adding --user-install instead of using sudo:

gem install mygem --user-install

For the Windows OS, I used Fiddler to work around the issue.

Run gem:

$ gem install --http-proxy http://localhost:8888 $gem_name

You just add the following line to your local ~/.gemrc file (it is in your home folder):

gem: --no-document

or you can add this line to the global gemrc config file.

Here is how to find it (in Linux):

strace gem source 2>&1 | grep gemrc

The --no-document option is documented in the RubyGems CLI Reference.