Why do I get "write permission" errors installing Rails?

ruby, ruby-on-rails, rvm

Solution

The most likely reason you're getting the error:

(Gem::FilePermissionError) You don't have write permissions into the /home/vikas/.rvm/gems/ruby-1.9.2-p320/bin directory. 

Is because, at some point, you used `sudo` or were running as root when you use RVM to install a gem. When that happened, the ownership of files and/or folders changed to root's permissions, which you can't override running as you.

You don't want to run as root, or use `sudo` EVER when running `rvm` or `gem` commands if you have a RVM installation to provide Ruby in a sandbox in your home directory.

To fix this, try this command:

sudo chown -R vikas ~/.rvm

That will use `sudo` to change ownership of all files in the ~/.rvm directory to your own account, from the "root" user. This will take at least a few seconds so let it run.

Once that has run, you should be able to switch to each of your Rubies and delete the installed Rails:

rvm use 1.9.2
gem uninstall rails
gem install rails -v 3.2.13

Then:

rvm use 2.0.0
gem uninstall rails
gem install rails -v [whatever version you want]
gem install rails -v 

Problem

Original source