pyenv does not affect the python being used and activate does not exist

Question

I am using a pyenv guide from here Managing Multiple Python Versions With pyenv

I have already created a 3.6.7 version:

13:24:51/hercl $pyenv versions
  system
* 3.6.7 (set by /Users/steve/.pyenv/version)

I made 3.6.7 global:

pyenv global 3.6.7

But the python being used is the system version

 $python -V
Python 3.9.9

Also there are many references to pyenv activate but that command does not exist??

 $pyenv commands
--version
commands
completions
exec
global
help
hooks
init
install
local
prefix
rehash
root
shell
shims
uninstall
version
version-file
version-file-read
version-file-write
version-name
version-origin
versions
whence
which

So how is the 3.6.7 version to be activated?

Update. here is how I installed and enabled pyenv:

git clone https://github.com/pyenv/pyenv.git ~/.pyenv
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n  eval "$(pyenv init -)"\nfi' >> ~/.bashrc

Also do I really need to uninstall the python versions already installed via brew? installing-pyenv-on-macos

Answer 1

While I had installed pyenv I had missed installing pyenv-virtualenv.

brew install pyenv-virtualenv

The following had already been added to ~/.bashrc but the second line had not been working. it does now

eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

And pyenv activate now runs fine

$pyenv activate 3.6.7
pyenv-virtualenv: virtualenv `/Users/steve/git/hercl/.venv' is already activated

Wow that was a confusing problem.

Update An additional step is needed: to manually add the $HOME/.pyenv/shims directory to the PATH. So now the last three lines of my ~/.bash_profile are:

export PATH=.:$HOME/.pyenv/bin:$HOME/.pyenv/shims:/opt/brew/bin:/opt/homebrew/bin:/usr/local/bin:/sbin:/usr/sbin:/usr/bin:/usr/local/bin:/bin
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"