installation

Requirements

$ sudo apt-get install -y make build-essential libssl-dev zlib1g-dev libbz2-dev \
libreadline-dev libsqlite3-dev wget curl llvm

install pyenv

$ cd ~
$ git clone git://github.com/yyuu/pyenv.git .pyenv
$ echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
$ echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
$ echo 'eval "$(pyenv init -)"' >> ~/.bashrc

install pyenv-virtualenv

$ git clone https://github.com/yyuu/pyenv-virtualenv.git ~/.pyenv/plugins/pyenv-virtualenv 
$ echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bashrc
$ exec $SHELL

Common Usage (Command Reference)

List all available versions

$ pyenv version -l

Install python2.7.8 to pyenv

$ pyenv install 2.7.8

List installed versions

$ pyenv versions
* system (set by /home/oopsmonk/.pyenv/version)
  2.7.8
  3.4.2

Creating a virtualenv

$ pyenv virtualenv 2.7.8 mypy-2.7.8

List virtualenvs

$ pyenv virtualenvs
  mypy-2.7.8 (created from /home/oopsmonk/.pyenv/versions/2.7.8)
  mypy-3.4.2 (created from /home/oopsmonk/.pyenv/versions/3.4.2)

# current versions 
$ pyenv versions
  * system (set by /home/oopsmonk/.pyenv/version)
  2.7.8
  3.4.2
  mypy-2.7.8
  mypy-3.4.2

Use python via virtualenv

# show current version
oopsmonk@VBox:~/markdown-note$ python --version
Python 2.7.6

# Change to other version
oopsmonk@VBox:~/markdown-note$ pyenv activate mypy-2.7.8
(mypy-2.7.8)oopsmonk@VBox:~/markdown-note$ python --version
Python 2.7.8

# Deactivate
(mypy-2.7.8)oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv deactivate
oopsmonk@oopsmonk-VBox:~/markdown-note$  python --version
Python 2.7.8
# Why current version is 2.7.8? it's supposed to 2.7.6.

oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv activate mypy-3.4.2
(mypy-3.4.2) oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv deactivate
oopsmonk@oopsmonk-VBox:~/markdown-note$ python --version
Python 3.4.2

oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv versions
  system
  2.7.8
  3.4.2
  mypy-2.7.8
* mypy-3.4.2 (set by PYENV_VERSION environment variable)

# delete a virtualenv   
$ pyenv uninstall mypy-2.7.8

# Go back to original system version  
$ alias pyenv_deactivate='pyenv deactivate && unset PYENV_VERSION'
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv activate mypy-3.4.2
(mypy-3.4.2) oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv_deactivate
oopsmonk@oopsmonk-VBox:~/markdown-note$ python --version
Python 2.7.6

Use python via pyenv

# Global python version
$ pyenv global 

# python version in current folder
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv local mypy-3.4.2
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv version
mypy-3.4.2 (set by /home/oopsmonk/markdown-note/.python-version)
oopsmonk@oopsmonk-VBox:~/markdown-note$ cd ..
oopsmonk@oopsmonk-VBox:~$ pyenv version
system (set by /home/oopsmonk/.pyenv/version)
oopsmonk@oopsmonk-VBox:~$ cd -
/home/oopsmonk/markdown-note
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv version
mypy-3.4.2 (set by /home/oopsmonk/markdown-note/.python-version)
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv local --unset
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv version
system (set by /home/oopsmonk/.pyenv/version)

# python version in current shell 
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv shell mypy-3.4.2
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv version
mypy-3.4.2 (set by PYENV_VERSION environment variable)
oopsmonk@oopsmonk-VBox:~/markdown-note$ cd -
/home/oopsmonk
oopsmonk@oopsmonk-VBox:~$ pyenv version
mypy-3.4.2 (set by PYENV_VERSION environment variable)
oopsmonk@oopsmonk-VBox:~$ pyenv shell --unset
oopsmonk@oopsmonk-VBox:~$ pyenv version
system (set by /home/oopsmonk/.pyenv/version)
oopsmonk@oopsmonk-VBox:~$ cd -
/home/oopsmonk/markdown-note
oopsmonk@oopsmonk-VBox:~/markdown-note$ pyenv version
system (set by /home/oopsmonk/.pyenv/version)