MyPew

Here I collect some notes about getting started with Pew (Python Env Wrapper) under Linux.

Pew is similar to virtualenvwrapper but I think it's much simpler to use. Pew provides just one command (pew) and all its functionalities are available through some options. Virtualenvwrapper seems to be a hack that is strongly connected to the Bash shell, while Pew works with various shells like bash, zsh, fish, powershell, etc. Pew is a much cleaner solution for working with virtual environments.

Configuration

I like to separate a project directory (with the source code) and its virtualenv directory (which contains the Python interpreter and the necessary modules). Thus, I have the following line in my .bashrc file:

export WORKON_HOME=$HOME/.virtualenvs

Virtualenvs will be created in this folder. And that's all. No more environment variables are needed.

Install Pew

sudo pip install pew

Then launch the command pew to see if it works. It will print a short help.

Creating a virtual environment

Create a project folder (for your source files) and launch the following command:

pew new -p=python2 project_name

Of course, instead of python2 you can also specify python3. You can also use PyPy, but for that check out the documentation of Pew.

Since I keep forgetting command line options, I made a script for creating a virt. env. called mk_venv.sh. Copy it to your project folder, edit the Python version at its beginning and launch it. The project name will be the current folder's name.

Activating a virtual environment

The pew command is the following:

pew workon project_name

Again, I don't like typing much, so I have another script for this task called on.sh. Copy it to the project folder and simply launch it if you want to activate the virt. env.

Deactivating a virtual environment

When you activate a virt. env. with Pew, it starts a new subshell. So simply quit from this subshell (with exit or Ctrl+D).

I have an alias for this, placed in my .bashrc file:

alias off='exit'

Summary

If you want to create a new project and you want to put it in a virt. env., then do this:

• create a project folder and copy the two files (mk_venv.sh and on.sh) in it
• create the virt. env. with ./mk_venv.sh
• activate the virt. env. with ./on.sh
• deactivate the virt. env. with off