Changes your $GEM_HOME.

• Updates $GEM_HOME, $GEM_PATH and $PATH.
  • Switches $GEM_HOME by pushing and popping gem directories to $GEM_PATH. This allows the stacking of multiple gem directories.
  • Prepends the new $GEM_HOME/bin to $PATH so it takes precedence.
• Compartmentalizes gems into .gem/$ruby_engine/$ruby_version.
• Plays nicely with RVM and chruby.
• Supports bash and zsh.
• Small (~90 LOC).
• Has tests.

Change the $GEM_HOME:

$ gem_home /path/to/project

Revert the $GEM_HOME:

$ gem_home -

Using with bundler:

$ cd padrino-app/
$ gem_home .
$ bundle install
Fetching gem metadata from https://rubygems.org/.........
Resolving dependencies...
Using rake 10.3.2
Using i18n 0.6.11
Using json 1.8.1
Using minitest 5.4.0
Using thread_safe 0.3.4
Installing tzinfo 1.2.2
Using activesupport 4.1.4
Using addressable 2.3.6
Installing builder 3.2.2
Using bundler 1.6.2
Using data_objects 0.10.14
Using dm-core 1.2.1
Using dm-aggregates 1.2.0
Using dm-do-adapter 1.2.0
Using dm-migrations 1.2.0
...    
$ padrino console # no `bundle exec` needed

• Notice how bundler re-used many of the gems from ~/.gem/... but installed missing gems into $PWD/.gem/....

wget -O gem_home-0.1.0.tar.gz https://github.com/postmodern/gem_home/archive/v0.1.0.tar.gz
tar -xzvf gem_home-0.1.0.tar.gz
cd gem_home-0.1.0/
sudo make install

All releases are PGP signed for security. Instructions on how to import my PGP key can be found on my blog. To verify that a release was not tampered with:

wget https://raw.github.com/postmodern/gem_home/master/pkg/gem_home-0.1.0.tar.gz.asc
gpg --verify gem_home-0.1.0.tar.gz.asc gem_home-0.1.0.tar.gz

gem_home can also be installed with homebrew:

curl https://github.com/postmodern/gem_home/blob/master/homebrew/gem_home.rb
brew install --HEAD -s gem_home.rb

Add the following to the ~/.bashrc or ~/.zshrc file:

source /usr/local/share/gem_home/gem_home.sh

If you wish to enable gem_home system-wide, add the following to /etc/profile.d/gem_home.sh:

if [ -n "$BASH_VERSION" ] || [ -n "$ZSH_VERSION" ]; then
  source /usr/local/share/gem_home/gem_home.sh
  ...
fi

This will prevent gem_home from accidentally being loaded by /bin/sh, which is not always the same as /bin/bash.

After removing the gem_home configuration:

$ sudo make uninstall

• gs
• gst
• ohmygems
• renv