goenv shell can't set env vars

[mark-5]

*****:~$ goenv versions
1.4
*****:~$ goenv shell 1.4
export GOENV_VERSION="1.4"
*****:~$ goenv version
goenv: couldn't find any version specified for use
*****:~$ echo $GOENV_VERSION

*****:~$

goenv shell fires off a subshell to run export GOENV_VERSION, which doesn't affect the env vars in the parent shell process. To work around this, most other *env's use *env init to setup an alias or shell function, which evals *env shell commands.