pass enter key from Java to Shell script

Question

I am trying a Java program to run multiple commands in unix environment. I would need to pass 'ENTER' after each command. Is there some way to pass enter in the InputStream.

        JSch jsch=new JSch();
        Session session=jsch.getSession("MYUSERNAME", "SERVER", 22);
        session.setPassword("MYPASSWORD");
        Properties config = new Properties();
        config.put("StrictHostKeyChecking", "no");
        session.setConfig(config);
        session.connect();

        Channel channel= session.openChannel("shell");
        channel.setInputStream(getInputStream("ls -l"));
        channel.setInputStream(getInputStream("\r\n"));
        channel.setInputStream(getInputStream("pwd"));
        channel.setInputStream(getInputStream("\r\n"));
        channel.connect();

When I do ls -l, I want to add enter here, so that the command is executed. getInputStream is a method to convert String into InputStream.

Any help will be appreciated.

Answer 1

According to the JSch javadoc, you must call setInputStream() or getOutputStream() before connect() . You can only do one of these, once.

For your purposes, getOutputStream() seems more appropriate. Once you have an OutputStream, you can wrap it in a PrintWriter to make sending commands easier.

Similarly you can use channel.getInputStream() to acquire an InputStream from which you can read results.

OutputStream os = channel.getOutputStream();
PrintWriter writer = new PrintWriter(os);
InputStream is = channel.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
channel.connect();
writer.println("ls -l");
String response = reader.readLine();
while(response != null) {
    // do something with response
    response = reader.readLine();
}
writer.println("pwd");

If you're determined to use setInputStream() instead of getOutputStream() then you can only do that once, so you'll have to put all your lines into one String:

    channel.setInputStream(getInputStream("ls -l\npwd\n"));

(I don't think you need \\r , but add it back in if necessary)

If you're not familiar with working with streams, writers and readers, do some study on these before working with JSch.