Execute an external program read its output, and print its exit status
import java.io.*;
/**
* ExecDemo shows how to execute an external program
* read its output, and print its exit status.
*/
public class ExecDemoWait {
public static void main(String argv[]) throws IOException {
// A Runtime object has methods for dealing with the OS
Runtime r = Runtime.getRuntime();
Process p; // Process tracks one external native process
BufferedReader is; // reader for output of process
String line;
// Our argv[0] contains the program to run; remaining elements
// of argv contain args for the target program. This is just
// what is needed for the String[] form of exec.
p = r.exec(argv);
System.out.println("In Main after exec");
// getInputStream gives an Input stream connected to
// the process p's standard output. Just use it to make
// a BufferedReader to readLine() what the program writes out.
is = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = is.readLine()) != null)
System.out.println(line);
System.out.println("In Main after EOF");
System.out.flush();
try {
p.waitFor(); // wait for process to complete
} catch (InterruptedException e) {
System.err.println(e); // "Can'tHappen"
return;
}
System.err.println("Process done, exit status was " + p.exitValue());
return;
}
}
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