pyenv-virtualenv/bin/pyenv-activate

#!/usr/bin/env bash
#
# Summary: Activate virtual environment
#
# Usage: pyenv activate <virtualenv>
#        pyenv activate --unset
#
# Activate a Python virtualenv environment in current shell.
# This acts almost as same as `pyenv shell`, but this invokes the `activate`
# script in your shell.
#
# <virtualenv> should be a string matching a Python version known to pyenv.

set -e
[ -n "$PYENV_DEBUG" ] && set -x

# Provide pyenv completions
if [ "$1" = "--complete" ]; then
  echo --unset
  exec pyenv-virtualenvs --bare
fi

{ printf "\x1B[31;1m"
  echo
  echo "Failed to activate virtualenv."
  echo
  echo "Perhaps pyenv-virtualenv has not been loaded into your shell properly."
  echo "Please restart current shell and try again."
  echo
  printf "\x1B[0m"
} 1>&2
exit 1