Open Radar

 
Summary:
The new security-related changes to El Capitan have resulted in Ruby's "gem install" command breaking in horrible ways.  There are two main issues:

1. The RubyGems installation directory is now set to "/Library/Ruby/Gems/2.0.0" which is not writable by the user.  Thus, "gem install" requires sudo, which is shouldn't.

2. The executables are not installed in a location in the user's $PATH, meaning the user either has to update their path or install manually into a directory that is in their path.

In a nutshell, we've gone from this:

$ gem install jekyll

to this:

$ sudo gem install -n /usr/local/bin jekyll

Steps to Reproduce:
Attempt to install a Ruby gem in 10.11 with a command similar to the following:

gem install jekyll

Expected Results:
The gem is installed.

Actual Results:
The following error is thrown:

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

Adding sudo allows the gem to install, but it is still not usable because it is installed in a location that is not in the user's $PATH.