javascript function to execute a cygwin bash shell script

This forum has helped me so much in the past that I thought I would post something that might help someone else.

In the course of writing automation scripts for use under DSS, I had the need to execute a bash shell script from within my javascript code.  I went nuts trying to find something on the web that would do this, but only found a few examples that were not completely what I wanted.  The following javascript function is intended to run under the rhino javascript interpreter that is used with DSS.  It is expecting to be invoked from a Windows environment that is running cygwin.  It takes a single character string that is a command to be executed as though it were typed into a bash shell command prompt.  It returns as the function's value a character string that contains the text written to the shell's stdout stream.  The shell's exit code is made available in the global variable bash_exit_code.  So here is the function:

// Define a function to execute shell commands on the PC host and return that shell's stdout

var bash_exit_code = 0;          // global to provide exit code from bash shell invocation

function bash(command)
{
  var c;           // a character of the shell's stdout stream
  var retval = "";          // the return value is the stdout of the shell

  var rt = Runtime.getRuntime();        // get current runTime object
  var shell = rt.exec("bash -c '" + command + "'");   // start the shell
  var shellIn = shell.getInputStream();        // this captures the output from the command

  while ((c = shellIn.read()) != -1)        // loop to capture shell's stdout
    {
      retval += String.fromCharCode(c);        // one character at a time
    }

  bash_exit_code = shell.waitFor();        // wait for the shell to finish and get the return code

  shellIn.close();          // close the shell's output stream

  return retval;
}

Hopefully, this will save someone else some time.  Enjoy!