コマンドひとつでrubyのバージョンを入れ替えられるやつ

#cd ~
#git clone git://github.com/sstephenson/rbenv.git .rbenv

[パスを通す]
# echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> .bash_profile
# echo 'eval "$(rbenv init -)"' >> .bash_profile
# source .bash_profile

# rbenv
rbenv 0.4.0-89-g14bc162

[ruby-buildのインストール]
rubyの手間を省く

# rbenv install
rbenv: no such command `install'

# git clone git://github.com/sstephenson/ruby-build.git .rbenv/plugins/ruby-build

# rbenv install
Usage: rbenv install [-f] [-kvp] <version>

# rbenv install -l
Available versions:
  1.8.6-p383

# rbenv install 1.9.3-p545 とか

# rbenv versions
* system (set by /root/.rbenv/version) ←手動でいれたやつ
  1.9.3-p545

# ruby -v
ruby 2.1.1p76 (2014-02-24 revision 45161) [x86_64-linux]

rubyのバージョンを変えてみる
# rbenv global 1.9.3-p545

# rbenv global 1.9.3-p545
# rbenv versions
  system
* 1.9.3-p545 (set by /root/.rbenv/version)

# ruby -v
ruby 1.9.3p545 (2014-02-24 revision 45159) [x86_64-linux]