How do I run multiple commands in SSH through Java?

Question

How do I run multiple commands in SSH using Java runtime?

the command: ssh [email protected] 'export MYVAR=this/dir/is/cool; /run/my/script /myscript; echo $MYVAR'

@Test
  public void testSSHcmd() throws Exception
  {
    StringBuilder cmd = new StringBuilder();

    cmd.append("ssh ");
    cmd.append("[email protected] ");
    cmd.append("'export ");
    cmd.append("MYVAR=this/dir/is/cool; ");
    cmd.append("/run/my/script/myScript; ");
    cmd.append("echo $MYVAR'");

    Process p = Runtime.getRuntime().exec(cmd.toString());
  }

The command by its self will work but when trying to execute from java run-time it does not. Any suggestions or advice?

What doesn't work? What happens?

dacwe
– dacwe

2011-09-30 14:10:11 +00:00
Commented Sep 30, 2011 at 14:10 — dacwe
– dacwe, Commented Sep 30, 2011 at 14:10
I love stackoverflow. Thanks everyone!

stackoverflow
– stackoverflow

2011-09-30 14:14:08 +00:00
Commented Sep 30, 2011 at 14:14 — stackoverflow
– stackoverflow, Commented Sep 30, 2011 at 14:14

dogbane · Accepted Answer · 2011-09-30 14:18:55Z

5

Use the newer ProcessBuilder class instead of Runtime.exec. You can construct one by specifying the program and its list of arguments as shown in my code below. You don't need to use single-quotes around the command. You should also read the stdout and stderr streams and waitFor for the process to finish.

ProcessBuilder pb = new ProcessBuilder("ssh", 
                                       "[email protected]", 
                                       "export MYVAR=this/dir/is/cool; /run/my/script/myScript; echo $MYVAR");
pb.redirectErrorStream(); //redirect stderr to stdout
Process process = pb.start();
InputStream inputStream = process.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
String line = null;
while((line = reader.readLine())!= null) {
    System.out.println(line);
}
process.waitFor();

answered Sep 30, 2011 at 14:18

dogbane

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1 Comment

AnandKumar Selvamani Over a year ago

Hi dogbane I need to run multiple ssh commands in a single run, the link which you shared was not clear to me. So ple if you have any clear document can you please share to me. Thanks

dacwe · Accepted Answer · 2011-09-30 14:04:59Z

If the Process just hangs I suspect that /run/my/script/myScript outputs something to stderr. You need to handle that output aswell as stdout:

public static void main(String[] args) throws Exception {
    String[] cmd = {"ssh", "root@localhost", "'ls asd; ls'" };
    final Process p = Runtime.getRuntime().exec(cmd);

    // ignore all errors (print to std err)
    new Thread() {
        @Override
        public void run() {
            try {
                BufferedReader err = new BufferedReader(
                        new InputStreamReader(p.getErrorStream()));
                String in;
                while((in = err.readLine()) != null)
                    System.err.println(in);
                err.close();
            } catch (IOException e) {}
        }
    }.start();

    // handle std out
    InputStreamReader isr = new InputStreamReader(p.getInputStream());
    BufferedReader reader = new BufferedReader(isr);

    StringBuilder ret = new StringBuilder();
    char[] data = new char[1024];
    int read;
    while ((read = reader.read(data)) != -1)
        ret.append(data, 0, read);
    reader.close();

    // wait for the exit code
    int exitCode = p.waitFor();
}

A.H. · Accepted Answer · 2011-09-30 14:43:30Z

1

The veriant of Runtime.exec you are calling splits the command string into several tokens which are then passed to ssh. What you need is one of the variants where you can provide a string array. Put the complete remote part into one argument while stripping the outer quotes. Example

Runtime.exec(new String[]{ 
    "ssh", 
    "[email protected]", 
    "export MYVAR=this/dir/is/cool; /run/my/script/myScript; echo $MYVAR"
});

That's it.

edited Sep 30, 2011 at 14:43

answered Sep 30, 2011 at 14:04

A.H.

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Comments

Chris Dail · Accepted Answer · 2011-09-30 13:56:49Z

0

You might want to take a look at the JSch library. It allows you to do all sorts of SSH things with remote hosts including executing commands and scripts.

They have examples listed here: http://www.jcraft.com/jsch/examples/

answered Sep 30, 2011 at 13:56

Chris Dail

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Comments

Jason Sturges · Accepted Answer · 2012-10-29 04:17:31Z

0

Here is the right way to do it:

Runtime rt=Runtime.getRuntime();
rt.exec("cmd.exe /c start <full path>");

For example:

Runtime rt=Runtime.getRuntime();
rt.exec("cmd.exe /c start C:/aa.txt");

edited Oct 29, 2012 at 4:17

Jason Sturges

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answered Apr 23, 2012 at 14:34

K.Selva Kumar

1

Comments

depicus · Accepted Answer · 2013-07-25 13:33:40Z

0

If you are using SSHJ from https://github.com/shikhar/sshj/

public static void main(String[] args) throws IOException {
    final SSHClient ssh = new SSHClient();
    ssh.loadKnownHosts();

    ssh.connect("10.x.x.x");
    try {
        //ssh.authPublickey(System.getProperty("root"));
        ssh.authPassword("user", "xxxx");
        final Session session = ssh.startSession();

        try {
            final Command cmd = session.exec("cd /backup; ls; ./backup.sh");
            System.out.println(IOUtils.readFully(cmd.getInputStream()).toString());
            cmd.join(5, TimeUnit.SECONDS);
            System.out.println("\n** exit status: " + cmd.getExitStatus());
        } finally {
            session.close();
        }
    } finally {
        ssh.disconnect();
    }
}

edited Jul 25, 2013 at 13:33

answered May 22, 2012 at 11:31

depicus

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4 Comments

AnandKumar Selvamani Over a year ago

Hi Depicus I need to run multiple ssh commands in a single run, the link which you shared was not clear to me. So ple if you have any clear document can you please share to me. Thanks

depicus Over a year ago

Hi Anand, basically separate each command with a ; and you should be good to go. The link works for me.

AnandKumar Selvamani Over a year ago

okay Depicus. I need to run multiple ssh commands with select query to view the status. I can't execute the query if you know how to execute select query please let me know. Here I Show the full commands. cd /aep/cu/scripts/;./dbutil.ksh E1QA;select * from tgpoa01.aud_trail_dtl where AUD_TRAIL_REC_ID = '-9223372036798689753'

depicus Over a year ago

The System.out.println(IOUtils.readFully(cmd.getInputStream()).toString()); line should return any output

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