Any tips on Controlling interactive bash shell on Cygwin via Java process?

Question

Ideally, I'd like to be able to control an interactive bash shell on Cygwin from a Java process. But for starters, I want to do 'ls > /cygdrive/c/fred.txt'. The little program to do this, below, doesn't work. It simply runs without error.
Any ideas? And also, any tips on doing a fully interactive shell?
--> Java program to test simple command:
package com.treelogic_swe.real_estate_explorer.utils;
import java.io.File;
import java.io.InputStream;
* Quick and dirty test of Java to Cygwin bash shell process control.
* Thanks to [email protected]
* re: http://groups.google.com/group/comp.lang.java.help/browse_thread/thread/914403fbdd1de127/40363d2e7cbae823?lnk=st&q=cygwin+shell+java+process+runtime&rnum=1&hl=en#40363d2e7cbae823
public class RunSystemCommand {   
    public static void main(String args[]) throws Throwable {
     // System command to run
     String cmd = "ls > /cygdrive/c/fred.txt";
        String [] sysArgs = { };
     // Set the working directory for the OS command processor
     File workDir = new File( "c:/cygwin/bin" );
     Process bash = Runtime.getRuntime().exec( cmd, sysArgs, workDir );
     InputStream bashIn = bash.getInputStream();
     while( bashIn.read() != -1 ); // Added, as otherwise the ls hangs.
     bash.waitFor();
}

Answer 1

Ideally, I'd like to be able to control an
interactive bash shell on Cygwin
What do you mean by this? Do you just want to start a bash shell, and have it's input and output come from and go to your Java program?
Please be specific about what you want, as there are a couple of interpretations for what you said. You need to understand the differences and relationships among terminals, shells, shell builtins, and executables.
You'll want to read this:
http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html
from a Java
process. But for starters, I want to do 'ls >
/cygdrive/c/fred.txt'. The little program to do
this, below, doesn't work. It simply runs without
error.
, <, |, and others are specific to the shell. When you're in a terminal, and you type ls > /tmp/zzz, it's the bash shell that interprets the >. Cygwin doesn't know anything about it. ls doesn't know anything about it.So if you want to to that, the command you'd execute from Java is not ls, but bash (or some other shell). You'd then tell bash to execute the rest. I'm not sure what the command line arg is for bash to tell it the rest of the command line args are a command that bash should interpret and execute. I think it might be -c like it is for zsh. So you'd need to do something like Runtie.getRuntime().exec("bash -c 'ls > /tmp/zzz'");