bundle install的作用：Make sure all dependencies in yourGemfileare available to your application.

尤其是你切换环境（切换不同的系统），这个时候在新的环境中可能各个Gem组件的版本不匹配，就需要运行bundle Install来保证当前环境的GEM FILES版本匹配。

[ruby]view plaincopy

print?

$ bundle install [--binstubs=PATH] [--clean] [--deployment] [--frozen]

[--full-index] [--gemfile=FILE] [--local] [--no-cache]

[--no-prune] [--path=PATH] [--quiet] [--shebang=STRING]

[--standalone=ARRAY] [--system] [--without=GROUP GROUP]

Options:

--binstubs: Generate bin stubs for bundled gems to ./bin

--clean: Run bundle clean automatically after install

--deployment: Install using defaults tuned for deployment environments

--frozen: Do not allow the Gemfile.lock to be updated after this install

--full-index: Use the rubygems modern index instead of the API endpoint

--gemfile: Use the specified gemfile instead of Gemfile

--local: Do not attempt to fetch gems remotely and use the gem cache instead

--no-cache: Don't update the existing gem cache.

--no-prune: Don't remove stale gems from the cache.

--path: Specify a different path than the system default ($BUNDLE_PATH or $GEM_HOME). Bundler will remember this value for future installs on this machine

--quiet: Only output warnings and errors.

--shebang: Specify a different shebang executable name than the default (usually 'ruby')

--standalone: Make a bundle that can work without the Bundler runtime

--system: Install to the system location ($BUNDLE_PATH or $GEM_HOME) even if the bundle was previously installed somewhere else for this application

--without: Exclude gems that are part of the specified named group.

rails new时bundle install有的时候非常慢

rails new xxx创建一个新项目，常常会卡在“run  bundle install”，有的时候快点，有的时候非常慢

C:\Work>rails new ptian1

create

create  README.rdoc

create  Rakefile

...

...

create  vendor/plugins/.gitkeep

run  bundle install

这是因为rails new时自动会运行bundle install，而bundle install会自动去rubygems.org查找是否有更新。但需要的gems我早安装好了，且不用更新，所以上面步骤就可省了。强烈建议rails党委取消rails new时自动查找gems更新功能！

解法很简单

rails new my_app --skip-bundle

cd my_app

bundle install --local

另外，最新版bundler速度提高不少，建议使用，也能提速

gem install bundler --pre