[ruby] How to avoid "cannot load such file -- utils/popen" from homebrew on OSX

I'm getting an error when I run brew in the terminal:

 /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- utils/popen (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/Library/Homebrew/utils.rb:6:in `<top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/Library/Homebrew/global.rb:9:in `<top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /usr/local/Library/brew.rb:16:in `<main>'

These are my gem settings:

- RUBYGEMS VERSION: 2.0.14
- RUBY VERSION: 2.0.0 (2014-02-24 patchlevel 451) [universal.x86_64-darwin13]
- INSTALLATION DIRECTORY: /Library/Ruby/Gems/2.0.0
- RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
- EXECUTABLE DIRECTORY: /usr/bin
- RUBYGEMS PLATFORMS:
  - ruby
  - universal-darwin-13
- GEM PATHS:
  - /Library/Ruby/Gems/2.0.0
  - /Users/ronaldkwan/.gem/ruby/2.0.0
  - /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/gems/2.0.0
- GEM CONFIGURATION:
  - :update_sources => true
  - :verbose => true
  - :backtrace => false
  - :bulk_threshold => 1000

To me it feels like you have missing header files for popen, which is a C system library.

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This issue should be fixed in the newest version of Homebrew. Try reinstalling it, which is described on the Homebrew home page.

Uninstall homebrew:

 ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

Then reinstall

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Warning: This script will remove: /Library/Caches/Homebrew/ - thks benjaminsila

The problem mainly occurs after updating OS X to El Capitan (OS X 10.11) or macOS Sierra (macOS 10.12).

This is because of file permission issues with El Capitan’s or later macOS's new SIP process. Try changing the permissions for the /usr/local directory:

$ sudo chown -R $(whoami):admin /usr/local  

If it still doesn't work, use these steps inside a terminal session and everything will be fine:

cd /usr/local/Library/Homebrew  
git reset --hard  
git clean -df
brew update

This may be because homebrew is not updated.

First I executed:

sudo chown -R $(whoami):admin /usr/local

Then:

cd $(brew --prefix) && git fetch origin && git reset --hard origin/master

To restore your Homebrew setup try this:

cd /usr/local/Homebrew/Library && git stash && git clean -d -f && git reset --hard && git pull

After updating to El Capitan, /usr/local has root:wheel rights.

Change the rights back to the user using:

sudo chown -R $(whoami):admin /usr/local

and:

brew doctor && brew update

This helped me to get Homebrew working again.

In my case I just needed to remove Homebrew's executable using:

sudo rm -f `which brew`

Then reinstall Homebrew:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

First, open a terminal session and run:

cd /usr/local/
git status

to see if Homebrew is clean.

If it's dirty, run:

git reset --hard && git clean -df

then

brew doctor
brew update

If it's still broken, try this in your session:

sudo rm /System/Library/Frameworks/Ruby.framework/Versions/Current
sudo ln -s /System/Library/Frameworks/Ruby.framework/Versions/1.8 /System/Library/Frameworks/Ruby.framework/Versions/Current

This will force Homebrew to use Ruby 1.8 from the system's installation.