SSH Linux commands

The controller of a Universal Robots cobot runs Linux. With SSH (Secure Shell), the SDK runs Linux commands on it, one by one or in a shell that keeps its session. This page shows both. To transfer files, see SFTP.

Prerequisites

• Secure Shell is enabled on the robot. On PolyScope, open Settings, Security, Secure Shell.
• The Linux user and its password: root on a robot, ur on URSim, easybot by default. The SDK uses ur and easybot when you set nothing.

A command runs with the rights of this user. A wrong command can stop the controller: test it on URSim first.

Run a command

SSH is disabled by default: set Ssh.EnableSsh in ConnectParameters. RunCommand runs a command and waits for its end. The returned SshCommand holds its output and its exit status.

static void Main(string[] args)
{
var robot = new UR();

var parameters = new ConnectParameters("192.168.0.1");

// SSH is disabled by default
parameters.Ssh.EnableSsh = true;

// "ur" and "easybot" by default
parameters.Ssh.Username = "root";
parameters.Ssh.Password = "easybot";

robot.Connect(parameters);

// Run a command and wait for its end
SshCommand command = robot.Ssh.RunCommand("df -h /programs");

string output = command.Result;  // standard output
int exitStatus = command.ExitStatus;
}
}

SshClient also works without UR: new SshClient(), then Connect(ip, username, password).

Open a shell

A shell keeps its session and its working directory, like a terminal. CreateShellStream opens one, with a terminal name, a size and a buffer size. DataReceived is raised when the shell writes text.

robot.Connect(parameters);
// A shell keeps its session and its working directory, like a terminal.
// Terminal name, columns, rows, width, height, buffer size
ShellStream shell = robot.Ssh.CreateShellStream("xterm", 80, 24, 800, 600, 1024);

// Raised for each text written by the shell
shell.DataReceived += (sender, e) => Console.Write(e.Line);

shell.WriteLine("cd /programs");
shell.WriteLine("ls -l");
}
}

Try it in the demo application

Everything on this page can be tried without writing code, in the Linux commands (SSH) page of the demo application.

The demo application is open source. The C# source of this page is SshControl.cs.

Reference