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how to use SSH in Java to return the result of command input of ubuntu's shell script to java [duplicate]

I am using a JSCH -SSH library to execute command in "shell" channel, but unable to find a way
to do 2 things:-
1) How to find whether the command is completely executed on remote unix box ?
2) How to capture the command output in String , instead of printing it on System.out console ?
Below is my code snippet which works fine to display shell command output on system.out
NOTE :I do NOT want to use ,"exec" channel, as it starts a new process for each command and does not remember "session" variables which were exported. I must use "shell" channel.
Below is my code snippet. Any help is appreciated.Thanks for your time.
try{
String commandToRun = "ls /tmp/*.log \n";
if(channel.isClosed())
channel=session.openChannel("shell");
byte[] bytes = commandToRun.getBytes();
ByteArrayInputStream bais=new ByteArrayInputStream(bytes);
channel.setInputStream(bais);
InputStream ins=channel.getInputStream();
channel.connect();
channel.setOutputStream(System.out);//This prints on console. Need 2 capture in String somehow?
//in-efficient way to allow command to execute completely on remote Unix machine
//DO NOT know a better way, to know when command is executed completely
Thread.sleep(5000L);
}
catch(Exception e){
System.out.println("Exception in executeCommand() --->"+ e.getMessage());
e.printStackTrace();
}

My solution may not be needed anymore for the OP, but anyone else who is searching for a solution to cover both conditions 1) waiting for the commands to finish on remote machine; and 2) capturing output as string; you can try this:
public class SshConnectionManager {
private static Session session;
private static ChannelShell channel;
private static String username = "";
private static String password = "";
private static String hostname = "";
private static Session getSession(){
if(session == null || !session.isConnected()){
session = connect(hostname,username,password);
}
return session;
}
private static Channel getChannel(){
if(channel == null || !channel.isConnected()){
try{
channel = (ChannelShell)getSession().openChannel("shell");
channel.connect();
}catch(Exception e){
System.out.println("Error while opening channel: "+ e);
}
}
return channel;
}
private static Session connect(String hostname, String username, String password){
JSch jSch = new JSch();
try {
session = jSch.getSession(username, hostname, 22);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.setPassword(password);
System.out.println("Connecting SSH to " + hostname + " - Please wait for few seconds... ");
session.connect();
System.out.println("Connected!");
}catch(Exception e){
System.out.println("An error occurred while connecting to "+hostname+": "+e);
}
return session;
}
private static void executeCommands(List<String> commands){
try{
Channel channel=getChannel();
System.out.println("Sending commands...");
sendCommands(channel, commands);
readChannelOutput(channel);
System.out.println("Finished sending commands!");
}catch(Exception e){
System.out.println("An error ocurred during executeCommands: "+e);
}
}
private static void sendCommands(Channel channel, List<String> commands){
try{
PrintStream out = new PrintStream(channel.getOutputStream());
out.println("#!/bin/bash");
for(String command : commands){
out.println(command);
}
out.println("exit");
out.flush();
}catch(Exception e){
System.out.println("Error while sending commands: "+ e);
}
}
private static void readChannelOutput(Channel channel){
byte[] buffer = new byte[1024];
try{
InputStream in = channel.getInputStream();
String line = "";
while (true){
while (in.available() > 0) {
int i = in.read(buffer, 0, 1024);
if (i < 0) {
break;
}
line = new String(buffer, 0, i);
System.out.println(line);
}
if(line.contains("logout")){
break;
}
if (channel.isClosed()){
break;
}
try {
Thread.sleep(1000);
} catch (Exception ee){}
}
}catch(Exception e){
System.out.println("Error while reading channel output: "+ e);
}
}
public static void close(){
channel.disconnect();
session.disconnect();
System.out.println("Disconnected channel and session");
}
public static void main(String[] args){
List<String> commands = new ArrayList<String>();
commands.add("ls -l");
executeCommands(commands);
close();
}
}
This solution is also useful if you need to send multiple commands at a time and keep the channel open to reuse it later.

For 2) u can use ByteArrayOutputStream
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
channel.setOutputStream(baos);
and then create new string from new String(baos.toByteArray())
For 1 have you tried to use 2>&1 at the end of your command?
String commandToRun = "ls /tmp/*.log 2>&1 \n";

Taking the example provided by Mihail, other info on the internets, and the feedback from Martin, here's a reworked solution using exec. Note that opening a session allows multiple commands to be sent, each one opening it's own channel for input/output.
Rant:I really dislike having to get the process' OUTPUT stream to write to. What an annoying paradigm (at least for me). What I wanted is the processes input stream to write my output to, and had an amazingly difficult time working out that it's inverted. Is it just me or does the following (pseudocode) not make way more sense??
channel.getInputStream().write("here's some text to write into my channel.");
String ret = channel.getOutputStream().getOutput();
Anyways, thanks to Mihail and Martin for their comments / input.
public class SSHConnectionManager {
private Session session;
private String username = "user";
private String password = "password";
private String hostname = "myhost";
public SSHConnectionManager() { }
public SSHConnectionManager(String hostname, String username, String password) {
this.hostname = hostname;
this.username = username;
this.password = password;
}
public void open() throws JSchException {
open(this.hostname, this.username, this.password);
}
public void open(String hostname, String username, String password) throws JSchException{
JSch jSch = new JSch();
session = jSch.getSession(username, hostname, 22);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no"); // not recommended
session.setConfig(config);
session.setPassword(password);
System.out.println("Connecting SSH to " + hostname + " - Please wait for few seconds... ");
session.connect();
System.out.println("Connected!");
}
public String runCommand(String command) throws JSchException, IOException {
String ret = "";
if (!session.isConnected())
throw new RuntimeException("Not connected to an open session. Call open() first!");
ChannelExec channel = null;
channel = (ChannelExec) session.openChannel("exec");
channel.setCommand(command);
channel.setInputStream(null);
PrintStream out = new PrintStream(channel.getOutputStream());
InputStream in = channel.getInputStream(); // channel.getInputStream();
channel.connect();
// you can also send input to your running process like so:
// String someInputToProcess = "something";
// out.println(someInputToProcess);
// out.flush();
ret = getChannelOutput(channel, in);
channel.disconnect();
System.out.println("Finished sending commands!");
return ret;
}
private String getChannelOutput(Channel channel, InputStream in) throws IOException{
byte[] buffer = new byte[1024];
StringBuilder strBuilder = new StringBuilder();
String line = "";
while (true){
while (in.available() > 0) {
int i = in.read(buffer, 0, 1024);
if (i < 0) {
break;
}
strBuilder.append(new String(buffer, 0, i));
System.out.println(line);
}
if(line.contains("logout")){
break;
}
if (channel.isClosed()){
break;
}
try {
Thread.sleep(1000);
} catch (Exception ee){}
}
return strBuilder.toString();
}
public void close(){
session.disconnect();
System.out.println("Disconnected channel and session");
}
public static void main(String[] args){
SSHConnectionManager ssh = new SSHConnectionManager();
try {
ssh.open();
String ret = ssh.runCommand("ls -l");
System.out.println(ret);
ssh.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

JSCH Console Read Showing Same Output for Different Commands

I am trying to send some commands to a router and trying to read the console output. But the problem is every time i send a new command i get the same output. I tried creating a new session after every command is executed but I still get the same output. I got a sample online and modified it according to my needs. When i run it as a standalone class, it works perfectly. But when deployed on a server, it just doesn't seem to work right. To be honest, I am only its only been a day or two I have used the JSCH and documentation is very sparse.
This is how my code reads:
private void writeCommand(String command) throws IOException, JSchException {
Channel channel = getChannel();
((ChannelExec) channel).setCommand(command.getBytes());
channel.setInputStream(null);
((ChannelExec) channel).setErrStream(System.err);
readChannelOutput(channel);
}
private void readChannelOutput(Channel channel) {
byte[] buffer = new byte[1024];
try {
InputStream inputStream = channel.getInputStream();
channel.connect();
while (true) {
while (inputStream.available() > 0) {
int i = inputStream.read(buffer, 0, 1024);
if (i < 0) {
break;
}
deviceOut.updateDeviceOutput(new String(buffer, 0, i));
}
if (channel.isClosed()) {
break;
}
}
disconnect();
} catch(IOException e) {
e.printstacktrace();
} catch (JSchException e) {
e.printstacktrace();
}
}
public Session getSession () throws Exception {
if (session == null || !session.isConnected()) {
session = connect(getUserid(), getIpaddress(), getPassword(), getPort());
}
return session;
}
protected Session connect(String userName, String hostname, String password, int port) throws Exception {
JSch jSch = new JSch();
try {
session = jSch.getSession(userName, hostname, port);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.setPassword(password);
logger.debug("Connecting SSH to " + getIpaddress() + " - Please wait for few seconds... ");
session.connect();
logger.debug("Connected!");
if (session.isConnected()) {
setConnectionState(DeviceConnection.LOGIN_COMPLETE);
} else {
setConnectionState(DeviceConnection.LOGIN_FAILED);
throw new Exception("Failed to login to device");
}
deviceOut = new DeviceOutput(getLogger());
return session;
} catch (JSchException e) {
disconnect();
e.printstacktrace();
} catch (PalException e) {
disconnect();
e.printstacktrace();
}
}
The commands that I am trying to send are
term len 512
and
show running-config | include hostname
But the output just stays the same. The first command should not even have any ouput to be honest. Is there anything I am doing wrong?

Java - JSCH Library - Run command which expects password

I am writing a java program which runs rsync on local Linux host to copy data to remote host. I am using jsch library. I looked at jsch examples, but I didn't find anything relevant.
I can't setup key authentication, so i was expecting to automated password entry of remote host when rsync command run prompts for the password.
I searched online for some ways of doing it, I don't find any easy way of doing it.
Following function just executes command fed to it, this function is part of a class which has server, username, password
public int executeCommand(String command) throws Exception {
JSch jsch = new JSch();
Session session = null;
Channel channel = null;
int exitCode;
try {
//Initialize session
session = jsch.getSession(this.username, this.server, 22);
session.setPassword(this.password);
session.setConfig("StrictHostKeyChecking", "no");
session.setConfig("PreferredAuthentications", "publickey,password");
//Connect
session.connect();
//Open a channel for communication
channel = session.openChannel("shell");
OutputStream ops = channel.getOutputStream();
PrintStream ps = new PrintStream(ops, true);
channel.connect();
logger.info("Sending command {} ",command);
ps.println(command);
ps.flush();
InputStream inputStream = channel.getInputStream();
processOutput(inputStream, "password:", timeout);
logger.info("Sending password.");
ps.println(this.targetPassword);
ps.flush();
processOutput(inputStream, "total size is", timeout);
//Get the process exit code
String exitCodeCommand = "echo $?";
logger.info("Sending command {} ",exitCodeCommand);
ps.println(exitCodeCommand);
ps.flush();
String exitCodeOutput = processOutput(inputStream, "", 0.5);
String[] outputArray = exitCodeOutput.split(System.lineSeparator());
if (outputArray.length < 2) {
String msg = String.format("Exit code of command $1%s is invalid %2$s", exitCodeCommand,
exitCodeOutput);
throw new Exception(msg);
}
try {
exitCode = Integer.parseInt(outputArray[1]);
} catch (NumberFormatException nfe) {
logger.error("Exception occurred while parsing {}", outputArray[1], nfe);
String msg = String.format("Exit code of command $1%s is invalid %2$s. Exit code parsed %3$s is " +
"not an integer", exitCodeCommand, exitCodeOutput, outputArray[2]);
throw new Exception(msg);
}
logger.info("Exit code {}", exitCode);
inputStream.close();
ps.close();
channel.disconnect();
session.disconnect();
} catch (JSchException e) {
logger.error("Exception occurred while creating session with {}. Error message {}", this.server, e
.getMessage(), e);
} catch (IOException e) {
logger.error("Exception occurred while creating performing IO with server {}. Error message {}", this
.server, e.getMessage(), e);
} finally {
logger.info("Closing channels");
if (channel != null && !channel.isClosed()) {
channel.disconnect();
}
if (session != null) {
session.disconnect();
}
}
return exitCode;
}
private String processOutput(InputStream inputStream, String outToFind, double timeout) throws Exception {
byte[] bt = new byte[1024];
StringBuilder builder = new StringBuilder();
double timeoutBeforeExit = timeout * 1000 * 60;
double timeElapsed = 0;
while (true) {
try {
while (inputStream.available() > 0) {
int i = inputStream.read(bt, 0, 1024);
if (i < 0) {
break;
}
String str = new String(bt, 0, i);
builder.append(str);
//displays the output of the command executed for debug purpose.
logger.info(str);
if (str.contains(outToFind)) {
logger.info("{} output is found.", outToFind);
return builder.toString();
} else {
logger.info("{} is not matched", str);
}
}
} catch (IOException e) {
logger.error("Exception occurred while creating performing IO with server {}. Error message {}", this
.server, e.getMessage(), e);
throw new Exception(e.getMessage());
}
timeElapsed = timeElapsed + SLEEP_TIME;
if (timeElapsed >= timeoutBeforeExit) {
throw new Exception("Timeout while waiting for output.");
}
try {
Thread.sleep(SLEEP_TIME);
} catch (InterruptedException e) {
logger.warn("Benign exception occurred inputStream thread sleep. Continuing.", e);
}
}
}

You can try the below code. It automatically reads the provided password and continue with running the next commands.
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
JSch jsch = new JSch();
Session session=jsch.getSession(user, host, 22);
session.setPassword(password);
session.setConfig(config);
session.connect();
System.out.println("Connected");
Channel channel=session.openChannel("exec");
//write the command, which expects password
((ChannelExec)channel).setCommand("command");
((ChannelExec)channel).setErrStream(System.err);
((ChannelExec)channel).setPty(true);
System.out.println("Password taken");
InputStream in=channel.getInputStream();
channel.connect();
OutputStream out=channel.getOutputStream();
//give the password below
out.write(("password\n").getBytes());
out.flush();
//write your commands
PrintStream out1= new PrintStream(out);
out1.println("command1");
out1.println("command2");
...................
out1.flush();

ssh appliance through Java, execuate commands and get response from commands

I am trying to ssh an appliance through java code and I encountered with errors. I am using
(http://www.jcraft.com/ )'s jar. Now here are my problems
How can I execuate multiple commands in chell using java? (jcreft lib or someother)
How can get output from following code (conversion of outputstream)
OutputStream out = System.out;
PrintStream ps = new PrintStream(out);
Here is code's snap
public static String LoginAppliance(String host, String ID )throws JSchException, InterruptedException, IOException
{
String result="";
String command = "_shell\n";
JSch jsch = new JSch();
Session session = jsch.getSession(user, host, 22);
session.setPassword(password);
session.setConfig("StrictHostKeyChecking", "no");
session.connect(10*1000);
Channel channel = session.openChannel("shell");
InputStream is = new ByteArrayInputStream(command.getBytes());
channel.setInputStream(is);
channel.setOutputStream(System.out);
OutputStream out = System.out;
PrintStream ps = new PrintStream(out);
channel.connect(15 * 1000);
Thread.sleep(3*1000);
channel.disconnect();
session.disconnect();
return (result);
}
It will really helpful for me.

Multiple commands can be separated by a semicolon (;) like:
String command = "echo 'hello';echo 'hello2'\n";
To get the result as a string instead of printing it to the console like:
ByteArrayOutputStream out = new ByteArrayOutputStream();
channel.setOutputStream(out);
...
return out.toString();

I misunderstood the question. I took a look on the documentation of Jsch and this was the easiest way for me to make it work:
import java.io.IOException;
import java.io.InputStream;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
public class Main {
public static void main(String[] args) {
String host = "theAddress";
String user = "root";
String password = "thePassword";
JSch jsch = new JSch();
Session session = null;
try {
session = jsch.getSession(user, host, 22);
session.setPassword(password);
session.setConfig("StrictHostKeyChecking", "no");
session.connect(10000);
System.out.println("-->" + runCommand("echo 'hello'", session)); // -->hello
System.out.println("-->" + runCommand("whoami", session)); // -->root
System.out.println("-->" + runCommand("date", session)); // -->Thu Mar 13 23:45:39 CET 2014
} catch (Exception e) {
e.printStackTrace();
} finally {
if (session != null) {
session.disconnect();
}
}
}
private static String runCommand(String string, Session session) {
ChannelExec channel = null;
try {
channel = (ChannelExec) session.openChannel("exec");
channel.setCommand(string);
channel.connect();
return readOutput(channel);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (channel != null) {
channel.disconnect();
}
}
return null;
}
private static String readOutput(ChannelExec channel) throws IOException {
// code from: http://www.jcraft.com/jsch/examples/Exec.java.html
StringBuilder sb = new StringBuilder();
InputStream in = channel.getInputStream();
byte[] tmp = new byte[1024];
while (true) {
while (in.available() > 0) {
int i = in.read(tmp, 0, 1024);
if (i < 0)
break;
sb.append(new String(tmp, 0, i));
}
if (channel.isClosed()) {
break;
}
try {
Thread.sleep(1000);
} catch (Exception e) {}
}
return sb.toString();
}
}

Jsch - Exit after Shell Script Execution

I'm trying to write a Java Program using Jsch where in I want to start the execution of a shell script using the program and exit the program once the execution of the shell script has been completed.
String userName = "";
String hostName = "";
String password = "";
JSch javaSecureChannel = new JSch();
Session jschSession = null;
Channel jschChannel = null;
try {
jschSession = javaSecureChannel.getSession(userName, hostName, 22);
Properties configurationProperties = new Properties();
configurationProperties.put("StrictHostKeyChecking", "no");
jschSession.setConfig(configurationProperties);
jschSession.setPassword(password);
jschSession.connect();
jschChannel = null;
jschChannel = jschSession.openChannel("shell");
jschChannel.setOutputStream(System.out);
File shellScript = createShellScript();
FileInputStream fin = new FileInputStream(shellScript);
byte fileContent[] = new byte[(int) shellScript.length()];
fin.read(fileContent);
InputStream in = new ByteArrayInputStream(fileContent);
jschChannel.setInputStream(in);
jschChannel.connect();
while(true){
//if(jschChannel.isClosed)
if(jschChannel.getExitStatus() == 0){
System.out.println("exit-status: " + jschChannel.getExitStatus());
break;
}
try{
Thread.sleep(1000);
}catch(Exception ee){
ee.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
}
jschChannel.disconnect();
jschSession.disconnect();
System.out.println("Done...!!!");
createShellScript method is as follows.
String temporaryShellFileName = "shellscript.sh";
File fileStream = new File(temporaryShellFileName);
try {
PrintStream outStream = new PrintStream(new FileOutputStream(fileStream));
outStream.println("#!/bin/bash");
outStream.println("cd /u01/app/java/gids4x/Test");
outStream.println("Test_with_NULL.sh");
outStream.close();
} catch (Exception e) {
System.err.println("Error: " + e.getMessage());
}
Using the above code, I'm able to start the execution of the shell script. However, I'm not bale to terminate the program execution even after the execution of the program is completed i.e. after the execution of the Script completes.
Can you please suggest what needs to be done exactly?

I also faced the same issue and resolved it by using below two steps :
1. Sending last command as "exit"
2. Putting my mail thread sleep until channel is open
Please find the code as below :
public static void main(String[] arg){
Channel channel=null;
Session session=null;
try{
JSch.setLogger(new MyLogger());
JSch jsch=new JSch();
jsch.addIdentity("C:\\testLinuxKey.key");
String host=null;
if(arg.length>0){
host=arg[0];
}
else{
host=JOptionPane.showInputDialog("Enter username#hostname",
System.getProperty("user.name")+
"#localhost");
}
String user=host.substring(0, host.indexOf('#'));
host=host.substring(host.indexOf('#')+1);
session=jsch.getSession(user, host, 22);
// username and password will be given via UserInfo interface.
UserInfo ui=new MyUserInfo();
session.setUserInfo(ui);
session.connect();
channel=session.openChannel("shell");
//channel.setInputStream(System.in);
channel.setOutputStream(System.out);
String temporaryShellFileName = "shellscript.sh";
File fileStream = new File(temporaryShellFileName);
try {
PrintStream outStream = new PrintStream(new FileOutputStream(fileStream));
outStream.println("id");
outStream.println("sudo bash");
outStream.println("cd /tmp/");
outStream.println("/tmp/wasinfo.sh");
outStream.println("exit");
outStream.println("exit");
outStream.close();
FileInputStream fin = new FileInputStream(fileStream);
byte fileContent[] = new byte[(int) fileStream.length()];
fin.read(fileContent);
InputStream in = new ByteArrayInputStream(fileContent);
channel.setInputStream(in);
} catch (Exception e) {
System.err.println("Error: " + e.getMessage());
}
channel.connect();
while(channel.isConnected())
{
System.out.println("----- Channel On ----");
Thread.currentThread().sleep(5000);
}
channel.disconnect();
session.disconnect();
}
catch(Exception e){
System.out.println(e);
channel.disconnect();
session.disconnect();
}
System.out.println("Main End");
}

I had a similar problem. I was running a shell in a window but couldn't get Java to terminate when the window was closed. I solved it by closing the input stream.