asdf shell: set plugin version for shell session only

[noraj]

We would like a command to set a version of a plugin for the current shell session only.

Describe the solution you'd like

Add asdf shell in addition to asdf {global, local} to set a version only for the current shell session.

Describe similar asdf features and why they are not sufficient

rbenv is the core project that gave birth to nodenv, pyenv, phpenv, env. It seems that asdf is totally inspired from rbenv using the same principles so I'm very surprised rbenv shell is not implemented.

Describe workarounds you've considered

It's already possible to set a version just for a shell session via environment variables but it's not very handy.

[Stratus3D]

This command actually already exists, and does exactly what you are describing.

@jthegedus what do you think about adding documention for asdf shell to this section of the website? https://asdf-vm.com/#/core-manage-versions?id=set-current-version We've got a info box that mentions the environment variable, but we don't mention the asdf shell command anywhere.

[jthegedus]

Yeah no problem :+1: It seems the asdf command doesn't list the asdf shell command either, so we should add it to that output as well.