Zsh Initialization Files and Non-Interactive SSH Execution

A common requirement for production environments is the consistent application of environment variables and aliases across both interactive sessions and automated remote executions. In Zsh, the shell distinguishes between interactive and non-interactive modes, which dictates which initialization files are sourced.

When executing a command via SSH (e.g., ssh user@host 'command'), the shell typically operates in non-interactive mode. This behavior often results in the bypass of .zshrc, where many developers centralize their configuration, leading to a discrepancy between the local development experience and production behavior.

To ensure portability and reliability, it is necessary to determine the optimal placement of configuration logic within the Zsh startup sequence (.zshenv, .zprofile, .zshrc, and .zlogin) to support both shell types without introducing redundant overhead.

• Which specific initialization file is guaranteed to be sourced during a non-interactive SSH command execution?
• What are the architectural implications of moving environment variable definitions from .zshrc to .zshenv regarding performance and shell startup time?