Function stdout_is_regular_file 

pub fn stdout_is_regular_file() -> bool

Whether this process’s stdout is a regular file (as opposed to a pipe, terminal, or device).

Strict mode uses this to catch murk export > secrets.env style redirects that would persist plaintext secrets to disk, while still allowing the eval "$(murk export)" pipe that direnv relies on. Unix-only; returns false elsewhere (can’t determine — don’t block).