Please review your shell configuration and check if there pyenv is configured properly. You will need following configuration to enable pyenv's shell feature.

if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi

For more information about installation instruction, please see README also.

Cool, thank you for answer. Worked for me.

thank you, U save my times

In shell window input
eval "$(pyenv init -)";
it work for me

Thank you

Thanks, but on macos, after default installation, pyenv init isn't evaluated in non-login shell (or my environment is messed up, but eval "$(pyenv init -)" is on .bash_profile only).

That means that in every non-login shell

pyenv --help

lists shell among other commands, but

$ pyenv shell
pyenv: no such command `shell'

of course this issue explains reasons, but at least message should be different.