With #3637 merged (fixed #2340), we now have an environment variable: CODER=true that's available in all Coder workspaces.

We should document that this variable is available, and can be used for e.g. dotfiles customization.

if [[ $CODER == true ]]; then
    # Inside a Coder workspace.
    custom_coder_logic
fi

We may potentially want to expand the number of env variables we have and are documented, see #2340 for a discussion about potential variables to add.

For reference, here's how Codespaces document theirs: Default environment variables for your codespace

Definition of done

The user can read Coder docs and find out about useful environment variables inside workspaces.