Ytukyg

I am new to programming and trying to install Rails on Ubuntu 18.10, but I get the following error when running $ gem install rails. How do I avoid this error and install rails?

ERROR:  While executing gem ... (Errno::EACCES)

    Permission denied @ dir_s_mkdir - /home/bernardo/.gem/specs

I'm running Ruby 2.5.3p105

Just go through the steps given in below link: https://gorails.com/setup/ubuntu/16.04
and make sure you install ruby using rvm and set is default ruby. Then install rails.
This will resolve your issue.

If still the problem is not resolved, then remove previously installed ruby and go through all the steps for ruby and rails installation.

Here are the steps that I took to install rbenv in ubuntu server

git clone https://github.com/rbenv/rbenv.git ~/.rbenv

echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc

echo 'eval "$(rbenv init -)"' >> ~/.bashrc

source ~/.bashrc

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build

rbenv -v

rbenv install 2.5.3

rbenv global 2.5.3

rbenv rehash

ruby -v

gem install bundler

# inside rails application

bundle install

Explanation:

• Line 1: clone rbenv project


• line 2-4: enter rbenv path and settings to your bashrc


• rbenv -v = check whether your rbenv is running correctly


• then install ruby version (I checked above you running version 2.5.3)


• rbenv global 2.5.3 (set version 2.5.3 in any folder paths)


• rbenv rehash (after you set global / local make sure you do rehash)

Never install a gem with sudo command.

use

gem install rails

instead of

sudo gem install rails 

Use sudo gem install rails May helps you.