Executing multiple bash commands using a Java JSch program after sudo login

Question

I am trying to execute multiple bash commands through a Java program which connects to a SSH using JSch. But after sudo login, I am unable to execute any bash commands. From what I have read, after sudo login, we enter into a sub-shell. I wish to use a single channel. I am clueless as to what to do next.

ChannelExec chnlex=(ChannelExec) session.openChannel("exec");

InputStream in = chnlex.getInputStream();

BufferedReader br=new BufferedReader(new InputStreamReader(in));
chnlex.setCommand("sudo -u appbatch -H  /opt/apptalk/local/bin/start_shell.sh -c <<exit");

chnlex.connect();

System.out.println("channel connection done");

String msg=null;
while((msg=br.readLine())!=null){
  System.out.println(msg);
}

chnlex.disconnect();
System.out.println("channel disconnected");

Also could anyone tell me how to write these bash commands in a separate function or file?

Answer 1

The sudo does not execute a new shell. But probably your start_shell.sh script does. You probably refer to sudo su. Maybe your script runs the su?

Anyway, to provide commands to the shell, feed the commands using shell's standard input:

ChannelExec channel = (ChannelExec) session.openChannel("exec");
channel.setCommand("sudo su");
channel.connect();
OutputStream out = channel.getOutputStream();
out.write(("command1\n").getBytes());
out.write(("command2\n").getBytes());
out.flush();

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The sudo/su are commands as any other, so it's actually the same as a very generic question:
Providing input/subcommands to command executed over SSH with JSch

Also see Running command after sudo login, which answers a more generic question on sudo su, without an unclear use of some unknown shell script.