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request about scp command (QProcess) using qt

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  • H hlowd

    I am writing a Windows -> Linux scp file transfer code using qt.

    Simple commands such as ipconfig and ping work, but the scp command does not.
    When using the ipconfig, ping command, the nRet value is 0, and when using the scp command, the nRet value is -2.
    What part can I fix?

    ps) This command operates normally in the Windows cmd window.

    Below is the full code.
    QString command = ui->m_edit->text();

    QProcess* process = new QProcess(this);

    // command - ipconfig /all
    // command - ping xxx.xxx.xxx.xxx
    // command - scp [file] [remote name]@[remote ip]:[remote path]

    • ex) "scp file.ini user@192.168.0.1:\home\user\path"

    int nRet = process->execute(command);
    //process->start(command);

    QByteArray result = process->readAll();

    QMessageBox msgbx;
    msgbx.setText(result);
    msgbx.exec();

    jsulmJ Online
    jsulmJ Online
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #2

    @hlowd Please format your code properly, it is hard to read.
    How does the command look exactly?
    Keep in mind that you have to pass the executable and its parameters as extra parameters to QProcess::start as shown in documentation. And please add error handling to see what goes wrong.
    Another comment: you're doing readAll() just after executing the command. This is not going to work. Either use waitForReadyRead or (better) connect a slot to readyRead signal and call readAll there.

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    0
    • H hlowd

      I am writing a Windows -> Linux scp file transfer code using qt.

      Simple commands such as ipconfig and ping work, but the scp command does not.
      When using the ipconfig, ping command, the nRet value is 0, and when using the scp command, the nRet value is -2.
      What part can I fix?

      ps) This command operates normally in the Windows cmd window.

      Below is the full code.
      QString command = ui->m_edit->text();

      QProcess* process = new QProcess(this);

      // command - ipconfig /all
      // command - ping xxx.xxx.xxx.xxx
      // command - scp [file] [remote name]@[remote ip]:[remote path]

      • ex) "scp file.ini user@192.168.0.1:\home\user\path"

      int nRet = process->execute(command);
      //process->start(command);

      QByteArray result = process->readAll();

      QMessageBox msgbx;
      msgbx.setText(result);
      msgbx.exec();

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #3

      @hlowd Your literal C++ string "scp file.ini user@192.168.0.1:\home\user\path" has single backslashes in it.

      H 1 Reply Last reply
      2
      • JonBJ JonB

        @hlowd Your literal C++ string "scp file.ini user@192.168.0.1:\home\user\path" has single backslashes in it.

        H Offline
        H Offline
        hlowd
        wrote on last edited by
        #4
        This post is deleted!
        1 Reply Last reply
        0
        • H Offline
          H Offline
          hlowd
          wrote on last edited by
          #5

          @JonB
          hello.

          In the actual code, I entered two backslashes.

          Additionally, by using the exeexcute function rather than the start function, no additional parameters were entered, and a response was received immediately.

          Only the scp command did not work.

          jsulmJ H 2 Replies Last reply
          0
          • H hlowd

            @JonB
            hello.

            In the actual code, I entered two backslashes.

            Additionally, by using the exeexcute function rather than the start function, no additional parameters were entered, and a response was received immediately.

            Only the scp command did not work.

            jsulmJ Online
            jsulmJ Online
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #6

            @hlowd said in request about scp command (QProcess) using qt:

            In the actual code, I entered two backslashes

            Please post real code you're using to avoid such confusion.
            "Only the scp command did not work" - so does it work now or not?
            Did you add error handling as suggested?

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            1 Reply Last reply
            0
            • H hlowd

              @JonB
              hello.

              In the actual code, I entered two backslashes.

              Additionally, by using the exeexcute function rather than the start function, no additional parameters were entered, and a response was received immediately.

              Only the scp command did not work.

              H Offline
              H Offline
              hlowd
              wrote on last edited by hlowd
              #7

              @hlowd

              This is the original source code.
              What's wrong?

              ps) I added two backslashes to the content, but only one is visible.

              //-----------------------------------
              // header
              //-----------------------------------
              #ifndef MAINWINDOW_H
              #define MAINWINDOW_H

              #include <QMainWindow>
              #include <QProcess>

              QT_BEGIN_NAMESPACE
              namespace Ui { class MainWindow; }
              QT_END_NAMESPACE

              class MainWindow : public QMainWindow
              {
              Q_OBJECT

              public:
              MainWindow(QWidget *parent = nullptr);
              ~MainWindow();
              QProcess *m_process;

              private slots:
              void on_pushButton_clicked();
              void readOutput();

              private:
              Ui::MainWindow *ui;
              };
              #endif // MAINWINDOW_H

              //----------------------------------------
              //cpp
              //-----------------------------------------
              #include "mainwindow.h"
              #include "ui_mainwindow.h"
              #include <qDebug>

              MainWindow::MainWindow(QWidget *parent)
              : QMainWindow(parent)
              , ui(new Ui::MainWindow)
              {
              ui->setupUi(this);
              }

              MainWindow::~MainWindow()
              {
              delete ui;
              }

              void MainWindow::on_pushButton_clicked()
              {
              m_process = new QProcess(this);
              QStringList listArguments;

              #if 0
              QString strParam = "scp";
              listArguments << "D:\SVN\Work\test\a.ini user@192.168.1.250:\home\user\SW\";
              #else
              QString strParam = "ipconfig";
              listArguments << "/all";
              #endif
              connect(m_process, SIGNAL(readyReadStandardError()), this, SLOT(readOutput()));
              connect(m_process, SIGNAL(readyReadStandardOutput()), this, SLOT(readOutput()));
              connect(m_process, SIGNAL(errorOccurred()), this, SLOT(readOutput()));

              m_process->start(strParam, listArguments);
              m_process->waitForFinished();
              
              if(m_process)
                  delete m_process;
              

              }

              void MainWindow::readOutput()
              {
              QString StdOut = m_process->readAllStandardOutput();
              QString StdError = m_process->readAllStandardError();
              QString StdError1 = m_process->errorString();
              qDebug() << "======================================\n";
              qDebug() << StdOut;
              qDebug() << StdError;
              qDebug() << StdError1;
              qDebug() << "======================================\n";
              }

              jsulmJ H 2 Replies Last reply
              0
              • H hlowd

                @hlowd

                This is the original source code.
                What's wrong?

                ps) I added two backslashes to the content, but only one is visible.

                //-----------------------------------
                // header
                //-----------------------------------
                #ifndef MAINWINDOW_H
                #define MAINWINDOW_H

                #include <QMainWindow>
                #include <QProcess>

                QT_BEGIN_NAMESPACE
                namespace Ui { class MainWindow; }
                QT_END_NAMESPACE

                class MainWindow : public QMainWindow
                {
                Q_OBJECT

                public:
                MainWindow(QWidget *parent = nullptr);
                ~MainWindow();
                QProcess *m_process;

                private slots:
                void on_pushButton_clicked();
                void readOutput();

                private:
                Ui::MainWindow *ui;
                };
                #endif // MAINWINDOW_H

                //----------------------------------------
                //cpp
                //-----------------------------------------
                #include "mainwindow.h"
                #include "ui_mainwindow.h"
                #include <qDebug>

                MainWindow::MainWindow(QWidget *parent)
                : QMainWindow(parent)
                , ui(new Ui::MainWindow)
                {
                ui->setupUi(this);
                }

                MainWindow::~MainWindow()
                {
                delete ui;
                }

                void MainWindow::on_pushButton_clicked()
                {
                m_process = new QProcess(this);
                QStringList listArguments;

                #if 0
                QString strParam = "scp";
                listArguments << "D:\SVN\Work\test\a.ini user@192.168.1.250:\home\user\SW\";
                #else
                QString strParam = "ipconfig";
                listArguments << "/all";
                #endif
                connect(m_process, SIGNAL(readyReadStandardError()), this, SLOT(readOutput()));
                connect(m_process, SIGNAL(readyReadStandardOutput()), this, SLOT(readOutput()));
                connect(m_process, SIGNAL(errorOccurred()), this, SLOT(readOutput()));

                m_process->start(strParam, listArguments);
                m_process->waitForFinished();
                
                if(m_process)
                    delete m_process;
                

                }

                void MainWindow::readOutput()
                {
                QString StdOut = m_process->readAllStandardOutput();
                QString StdError = m_process->readAllStandardError();
                QString StdError1 = m_process->errorString();
                qDebug() << "======================================\n";
                qDebug() << StdOut;
                qDebug() << StdError;
                qDebug() << StdError1;
                qDebug() << "======================================\n";
                }

                jsulmJ Online
                jsulmJ Online
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @hlowd said in request about scp command (QProcess) using qt:

                listArguments << "D:\SVN\Work\test\a.ini user@192.168.1.250:\home\user\SW";

                Is this really your real code?!
                You again have single back-slashes.
                And why do you use back-slashes for paths on Linux side?
                Also that line should be:

                listArguments << "D:\\SVN\\Work\\test\\a.ini" <<  "user@192.168.1.250:/home/user/SW/";
                

                And please format you code properly.

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                1 Reply Last reply
                1
                • H hlowd

                  @hlowd

                  This is the original source code.
                  What's wrong?

                  ps) I added two backslashes to the content, but only one is visible.

                  //-----------------------------------
                  // header
                  //-----------------------------------
                  #ifndef MAINWINDOW_H
                  #define MAINWINDOW_H

                  #include <QMainWindow>
                  #include <QProcess>

                  QT_BEGIN_NAMESPACE
                  namespace Ui { class MainWindow; }
                  QT_END_NAMESPACE

                  class MainWindow : public QMainWindow
                  {
                  Q_OBJECT

                  public:
                  MainWindow(QWidget *parent = nullptr);
                  ~MainWindow();
                  QProcess *m_process;

                  private slots:
                  void on_pushButton_clicked();
                  void readOutput();

                  private:
                  Ui::MainWindow *ui;
                  };
                  #endif // MAINWINDOW_H

                  //----------------------------------------
                  //cpp
                  //-----------------------------------------
                  #include "mainwindow.h"
                  #include "ui_mainwindow.h"
                  #include <qDebug>

                  MainWindow::MainWindow(QWidget *parent)
                  : QMainWindow(parent)
                  , ui(new Ui::MainWindow)
                  {
                  ui->setupUi(this);
                  }

                  MainWindow::~MainWindow()
                  {
                  delete ui;
                  }

                  void MainWindow::on_pushButton_clicked()
                  {
                  m_process = new QProcess(this);
                  QStringList listArguments;

                  #if 0
                  QString strParam = "scp";
                  listArguments << "D:\SVN\Work\test\a.ini user@192.168.1.250:\home\user\SW\";
                  #else
                  QString strParam = "ipconfig";
                  listArguments << "/all";
                  #endif
                  connect(m_process, SIGNAL(readyReadStandardError()), this, SLOT(readOutput()));
                  connect(m_process, SIGNAL(readyReadStandardOutput()), this, SLOT(readOutput()));
                  connect(m_process, SIGNAL(errorOccurred()), this, SLOT(readOutput()));

                  m_process->start(strParam, listArguments);
                  m_process->waitForFinished();
                  
                  if(m_process)
                      delete m_process;
                  

                  }

                  void MainWindow::readOutput()
                  {
                  QString StdOut = m_process->readAllStandardOutput();
                  QString StdError = m_process->readAllStandardError();
                  QString StdError1 = m_process->errorString();
                  qDebug() << "======================================\n";
                  qDebug() << StdOut;
                  qDebug() << StdError;
                  qDebug() << StdError1;
                  qDebug() << "======================================\n";
                  }

                  H Offline
                  H Offline
                  hlowd
                  wrote on last edited by
                  #9

                  @hlowd

                  I entered two words in the post, but only one is displayed on the screen...

                  jsulmJ H 2 Replies Last reply
                  0
                  • H hlowd

                    @hlowd

                    I entered two words in the post, but only one is displayed on the screen...

                    jsulmJ Online
                    jsulmJ Online
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    @hlowd said in request about scp command (QProcess) using qt:

                    I entered two words in the post, but only one is displayed on the screen...

                    Use code tags properly, then it will be shown correctly

                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                    1 Reply Last reply
                    0
                    • H hlowd

                      @hlowd

                      I entered two words in the post, but only one is displayed on the screen...

                      H Offline
                      H Offline
                      hlowd
                      wrote on last edited by
                      #11

                      @hlowd

                      listArguments << "D:\\SVN\\Work\\test\\a.ini" << "user@192.168.1.250:/home/user/SW/";

                      Even though I entered it like this, it is the same.
                      The response from start comes immediately, but the readOutput function is not called.

                      jsulmJ H 2 Replies Last reply
                      0
                      • H hlowd

                        @hlowd

                        listArguments << "D:\\SVN\\Work\\test\\a.ini" << "user@192.168.1.250:/home/user/SW/";

                        Even though I entered it like this, it is the same.
                        The response from start comes immediately, but the readOutput function is not called.

                        jsulmJ Online
                        jsulmJ Online
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #12

                        @hlowd said in request about scp command (QProcess) using qt:

                        but the readOutput function is not called

                        Probably because you're deleting m_process right after waitForFinished.
                        Are you sure scp.exe command is found?
                        Try with an absolute path to scp.exe to make sure it is actually found.

                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                        1 Reply Last reply
                        0
                        • H hlowd

                          @hlowd

                          listArguments << "D:\\SVN\\Work\\test\\a.ini" << "user@192.168.1.250:/home/user/SW/";

                          Even though I entered it like this, it is the same.
                          The response from start comes immediately, but the readOutput function is not called.

                          H Offline
                          H Offline
                          hlowd
                          wrote on last edited by
                          #13

                          @hlowd

                          The symptom is the same even if delete is not called.

                          If it is a command instruction rather than a code, the instruction will be executed normally.
                          The file is moved normally. (Windows -> Linux)

                          jsulmJ H 2 Replies Last reply
                          0
                          • H hlowd

                            @hlowd

                            The symptom is the same even if delete is not called.

                            If it is a command instruction rather than a code, the instruction will be executed normally.
                            The file is moved normally. (Windows -> Linux)

                            jsulmJ Online
                            jsulmJ Online
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #14

                            @hlowd Again: try with absolute path to scp.exe

                            https://forum.qt.io/topic/113070/qt-code-of-conduct

                            1 Reply Last reply
                            0
                            • H hlowd

                              @hlowd

                              The symptom is the same even if delete is not called.

                              If it is a command instruction rather than a code, the instruction will be executed normally.
                              The file is moved normally. (Windows -> Linux)

                              H Offline
                              H Offline
                              hlowd
                              wrote on last edited by hlowd
                              #15

                              @hlowd
                              There are files in that path.

                              C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                              
                              scp.exe
                              ssh-add.exe
                              ssh-agent.exe
                              ssh-keygen.exe
                              

                              // new code

                              QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                              

                              // error message

                              "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                              
                              JonBJ jsulmJ 2 Replies Last reply
                              0
                              • H hlowd

                                @hlowd
                                There are files in that path.

                                C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                                
                                scp.exe
                                ssh-add.exe
                                ssh-agent.exe
                                ssh-keygen.exe
                                

                                // new code

                                QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                                

                                // error message

                                "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                                
                                JonBJ Offline
                                JonBJ Offline
                                JonB
                                wrote on last edited by JonB
                                #16

                                @hlowd
                                If you want help on this, at least for my part, please make the effort to enclose your code blocks and literal extracts in the forums block quotes (</> button) as we have asked several times. It does not require much effort on your side.

                                By now you should be trying a command of scp, nothing else, no arguments, to verify that (a) it is found and can be run and (b) you can successfully read any output from it, e.g. presumably a "usage" message in this case.

                                1 Reply Last reply
                                0
                                • H hlowd

                                  @hlowd
                                  There are files in that path.

                                  C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                                  
                                  scp.exe
                                  ssh-add.exe
                                  ssh-agent.exe
                                  ssh-keygen.exe
                                  

                                  // new code

                                  QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                                  

                                  // error message

                                  "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                                  
                                  jsulmJ Online
                                  jsulmJ Online
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #17

                                  @hlowd said in request about scp command (QProcess) using qt:

                                  Can I do it this way?

                                  Yes, just try.
                                  I would also execute scp using this absolute path in a terminal to make sure it works.

                                  https://forum.qt.io/topic/113070/qt-code-of-conduct

                                  H 1 Reply Last reply
                                  0
                                  • jsulmJ jsulm

                                    @hlowd said in request about scp command (QProcess) using qt:

                                    Can I do it this way?

                                    Yes, just try.
                                    I would also execute scp using this absolute path in a terminal to make sure it works.

                                    H Offline
                                    H Offline
                                    hlowd
                                    wrote on last edited by
                                    #18

                                    @jsulm

                                    There are files in that path.

                                    C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                                    
                                    scp.exe
                                    ssh-add.exe
                                    ssh-agent.exe
                                    ssh-keygen.exe
                                    

                                    // new code

                                    QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                                    

                                    // error message

                                    "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                                    

                                    The same error occurs in the command prompt.

                                    JonBJ jsulmJ 2 Replies Last reply
                                    0
                                    • H hlowd

                                      @jsulm

                                      There are files in that path.

                                      C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                                      
                                      scp.exe
                                      ssh-add.exe
                                      ssh-agent.exe
                                      ssh-keygen.exe
                                      

                                      // new code

                                      QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                                      

                                      // error message

                                      "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                                      

                                      The same error occurs in the command prompt.

                                      JonBJ Offline
                                      JonBJ Offline
                                      JonB
                                      wrote on last edited by
                                      #19

                                      @hlowd
                                      I am not a total Windows expert, but I did not think you should ever attempt to run anything in the WinSxS area? You should be running the scp which is on your PATH (presumably).

                                      1 Reply Last reply
                                      0
                                      • H hlowd

                                        @jsulm

                                        There are files in that path.

                                        C:\Windows\WinSxS\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb
                                        
                                        scp.exe
                                        ssh-add.exe
                                        ssh-agent.exe
                                        ssh-keygen.exe
                                        

                                        // new code

                                        QString strParam = "C:\\Windows\\WinSxS\\amd64_openssh-common-components-onecore_31bf3856ad364e35_10.0.22621.1_none_1e3c4880a37d88bb\\scp.exe";
                                        

                                        // error message

                                        "CreateProcessW failed error:2 posix_spawn: No such file or directory"
                                        

                                        The same error occurs in the command prompt.

                                        jsulmJ Online
                                        jsulmJ Online
                                        jsulm
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #20

                                        @hlowd Did scp executable ever work for you in terminal? The path where it is located looks strange, don't know from where it comes. On my machine I have it here: c:\windows\System32\OpenSSH\scp.exe

                                        You can check where your scp.exe is located using this command:

                                        where scp
                                        

                                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                                        H 1 Reply Last reply
                                        2
                                        • jsulmJ jsulm

                                          @hlowd Did scp executable ever work for you in terminal? The path where it is located looks strange, don't know from where it comes. On my machine I have it here: c:\windows\System32\OpenSSH\scp.exe

                                          You can check where your scp.exe is located using this command:

                                          where scp
                                          
                                          H Offline
                                          H Offline
                                          hlowd
                                          wrote on last edited by
                                          #21

                                          @jsulm

                                          The scp.exe file exists in that path.

                                          C:\Windows\System32\OpenSSH
                                          

                                          I don't know why I couldn't find it using Explorer search.

                                          jsulmJ 1 Reply Last reply
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