Run a Command on an SSH Session Channel

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Demonstrates the Chilkat Ssh.SendReqExec method, which requests execution of a command on a session channel. The first argument is the channel number and the second is the command line. This example runs a command, reads the output until the channel closes, and prints it.

func chilkatTest() {
    var success: Bool = false

    //  Demonstrates the Ssh.SendReqExec method, which requests execution of a command on a session
    //  channel.  The 1st argument is the channel number and the 2nd is the command line.

    let ssh = CkoSsh()!

    var sshPort: Int = 22
    success = ssh.connect(hostname: "ssh.example.com", port: sshPort)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    var password: String? = "mySshPassword"

    success = ssh.authenticatePw(login: "mySshLogin", password: password)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  Open a session channel.  A negative return value indicates failure.
    var channelNum: Int = ssh.openSessionChannel().intValue
    if channelNum < 0 {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  Request execution of a command.  A true return means the server accepted the request; it
    //  does not mean the command itself succeeded.
    success = ssh.sendReqExec(channelNum: channelNum, command: "ls -l /tmp")
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    //  it, this call waits forever if the server never sends channel close.
    ssh.readTimeoutMs = 15000

    //  Read the command output until the server closes the channel.
    success = ssh.channelReceive(toClose: channelNum)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    var output: String? = ssh.getReceivedText(channelNum: channelNum, charset: "utf-8")
    if ssh.lastMethodSuccess == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    print("\(output!)")

    ssh.disconnect()

}