// A Runtime object has methods for dealing with the OS
Runtime r = Runtime.getRuntime();
// A process object tracks one external running process
Process p;
// file contains unsorted data
p = r.exec("sort sortdemo.txt");
// getInputStream gives an Input stream connected to
// the process p's standard output (and vice versa). We use
// that to construct a BufferedReader so we can readLine() it.
BufferedReader is = new BufferedReader(
new InputStreamReader(p.getInputStream()));
System.out.println("Here is your sorted data:");
String aLine;
while ((aLine = is.readLine()) != null)
System.out.println(aLine);
System.out.println("That is all, folks!");
return;
