pyenv: add page (#995)

pages/common/pyenv.md

@@ -0,0 +1,27 @@
+# pyenv  
+
+> Switch between multiple versions of Python easily.
+
+- List all available commands:
+
+`pyenv commands`
+
+- List all Python versions under the ${PYENV_ROOT}/versions directory:
+
+`pyenv versions`
+
+- Install a Python version under the ${PYENV_ROOT}/versions directory:
+
+`pyenv install {{2.7.10}}`
+
+- Uninstall a Python version under the ${PYENV_ROOT}/versions directory:
+
+`pyenv uninstall {{2.7.10}}`
+
+- Set Python version to be used globally in the current machine:
+
+`pyenv global {{2.7.10}}`
+
+- Set Python version to be used in the current directory and all directories below it:
+
+`pyenv local {{2.7.10}}`