Passing input to commands is an essential aspect of command execution in programming, particularly in Go. Two primary methods are used to funnel data into commands: command line arguments and the standard input stream. Command line arguments are passed as unique strings—allowing for effective handling of spaces through automatic escaping—while the standard input stream can be fed data via `io.reader`. Utilizing the `exec` package's `standard in pipe` offers a robust way to stream input into commands, automatically closing the pipe when the command completes. This functionality not only simplifies the process but also integrates seamlessly with various `IO` constructs, enabling complex input-output operations such as redirecting inputs to both a command and the standard output simultaneously—enhancing the versatility and power of command execution in applications.