...It provides macros and utilities that let you spawn external processes, redirect input/output, and pipe commands together, all without invoking a shell. You can write something like run_cmd!(ls -l | grep foo > out.txt) in a more declarative style, rather than manually wiring up file descriptors, handles, and child processes. The library also supports features like variable substitution, scoped environment settings, and defining custom commands (functions) that behave like built-ins. It hides much of the boilerplate of std::process::Command when you're doing simple task automations, but still allows full flexibility when needed. ...