rubygems - You don't have write permissions for the /var/lib/gems/2.3.0 directory

Question

I have ruby installed on my ubuntu 16.04.

$which ruby  

/usr/bin/ruby

$ruby -v 

ruby 2.3.0p0 (2015-12-25) [x86_64-linux-gnu]

$gem install bundler 

ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /var/lib/gems/2.3.0 directory.

Any help will be greatly appreciated!

Answer 1

You first need to uninstall the ruby installed by Ubuntu with something like sudo apt-get remove ruby.

Then reinstall ruby using rbenv and ruby-build according to their docs:

cd $HOME
sudo apt-get update
sudo apt install curl
curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt-get update
sudo apt-get install git-core zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common libffi-dev nodejs yarn

Now we will install rbenv (recommended, see docs)

cd
git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL

rbenv install 3.0.1
rbenv global 3.0.1
ruby -v

The last step is to install Bundler:

gem install bundler
rbenv rehash

Then enjoy!

Derek

Update: This answer has been updated and tested successfully on Ubuntu 20.04.