A bash function to create a Python PEP-370 virtual environment, similar to virtualenv but leaner

bash_functions.sh

# This is a shell (bash) function. you need to add it to your bashrc or bash_profile file

# Create a PEP-370 Python virtual environment
function create_env () {
    ENV=`readlink -f $1` || return 1
    mkdir $ENV || return 1
    mkdir $ENV/bin || return 1
    cat <<-EOF > $ENV/bin/activate
        # first check if other env is active
        [ x"$PYTHONUSERBASE" != x ] && echo "PYTHONUSERBASE already active from '$PYTHONUSERBASE'. Use 'deactivate' first." && return 1

	# setup pep-370
        # alternatively ENV=$(dirname $(readlink -f $BASH_SOURCE)/..) would make the activate script stateless
	export PYTHONUSERBASE=$ENV

	# configure pip
	export PIP_INSTALL_OPTION=--user

	# setup the bash prompt
	_OLD_PS1=\$PS1
	PS1="[$1]\$PS1"

	# setup the bash path
	_OLD_PATH=\$PATH
	PATH=\$PYTHONUSERBASE/bin:\$PATH

	# .. and at last allow for cleanup
	alias deactivate='PATH=\$_OLD_PATH; PS1=\$_OLD_PS1; unset PIP_INSTALL_OPTION; unset PYTHONUSERBASE; unalias deactivate'
	EOF
    echo "source $ENV/bin/activate in your shell to activate this environment."
}
# end of PEP-370 creator

Some documentation on http://damjan.softver.org.mk/wiki/pep-370