In this recipe, we will call a child process from the Rust code to the outside world and record its output values. A child process is created via the Command struct, which configures the spawning process. The child process, in general, is any other tool or application that you would run or start using specific shell commands. In Rust, we spawn these child processes from the main process, which is the main Rust application, and control them according to the need of the Rust application using the built-in methods that let us read errors, pass arguments, wait for the process to complete, parse the output, and more.