While this blog article is about a new feature of the Scheme-based Guix Linux package manager, it contans the following interesting observation about erroneous shell settings: "it’s not uncommon for the shell to mess up with the whole environment. Why? Because, contrary to documented practice, it’s quite common for users to define or override environment variables in the startup files of non-login shells, ~/.bashrc for Bash, ~/.zshrc for Zsh. Instead, environment variable definitions should go to the startup file of login shells—~/.bash_profile, ~/.profile, or similar. But let’s face it: it’s a subtle distinction that few of us know or care about."