diff --git a/src/backends/octave/octaveexpression.cpp b/src/backends/octave/octaveexpression.cpp
index aea518d2..0a85a035 100644
--- a/src/backends/octave/octaveexpression.cpp
+++ b/src/backends/octave/octaveexpression.cpp
@@ -1,188 +1,173 @@
 /*
     Copyright (C) 2010 Miha Čančula <miha.cancula@gmail.com>
 
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA  02110-1301, USA.
 */
 
 #include "octaveexpression.h"
 #include "octavesession.h"
 #include "defaultvariablemodel.h"
 
 #include "textresult.h"
 
 #include <QDebug>
 #include <QFile>
 #include <helpresult.h>
 
 
-static const char* printCommand = "cantor_print();";
+static const QLatin1String printCommand("cantor_print();");
 
 OctaveExpression::OctaveExpression(Cantor::Session* session, bool internal): Expression(session, internal),
     m_plotPending(false),
-    m_finished(false),
-    m_appendPlotCommand(false),
-    m_appendDot(false)
+    m_finished(false)
 {
     m_plotCommands << QLatin1String("plot") << QLatin1String("semilogx") << QLatin1String("semilogy") << QLatin1String("loglog")
                    << QLatin1String("polar") << QLatin1String("contour") << QLatin1String("bar")
                    << QLatin1String("stairs") << QLatin1String("errorbar")  << QLatin1String("sombrero")
                    << QLatin1String("hist") << QLatin1String("fplot") << QLatin1String("imshow")
                    << QLatin1String("stem") << QLatin1String("stem3") << QLatin1String("scatter") << QLatin1String("pareto") << QLatin1String("rose")
                    << QLatin1String("pie") << QLatin1String("quiver") << QLatin1String("compass") << QLatin1String("feather")
                    << QLatin1String("pcolor") << QLatin1String("area") << QLatin1String("fill") << QLatin1String("comet")
                    << QLatin1String("plotmatrix")
                    /* 3d-plots */
                    << QLatin1String("plot3")
                    << QLatin1String("mesh") << QLatin1String("meshc") << QLatin1String("meshz")
                    << QLatin1String("surf") << QLatin1String("surfc") << QLatin1String("surfl") << QLatin1String("surfnorm")
                    << QLatin1String("isosurface")<< QLatin1String("isonormals") << QLatin1String("isocaps")
                    /* 3d-plots defined by a function */
                    << QLatin1String("ezplot3") << QLatin1String("ezmesh") << QLatin1String("ezmeshc") << QLatin1String("ezsurf") << QLatin1String("ezsurfc");
     m_plotCommands << QLatin1String("cantor_plot2d") << QLatin1String("cantor_plot3d");
 }
 
 void OctaveExpression::interrupt()
 {
     qDebug() << "interrupt";
 
-    if (m_appendPlotCommand)
-        removeAppendedPlotCommand();
-
     setStatus(Interrupted);
 }
 
 void OctaveExpression::evaluate()
 {
     qDebug() << "evaluate";
     QString cmd = command();
     QStringList cmdWords = cmd.split(QRegExp(QLatin1String("\\b")), QString::SkipEmptyParts);
     if (!cmdWords.contains(QLatin1String("help")) && !cmdWords.contains(QLatin1String("completion_matches")))
     {
         foreach (const QString& plotCmd, m_plotCommands)
         {
             if (cmdWords.contains(plotCmd))
             {
                 setPlotPending(true);
                 qDebug() << "Executing a plot command";
                 break;
             }
         }
     }
-    if ( m_plotPending && !cmd.contains(QLatin1String("cantor_plot")) && !cmd.contains(QLatin1String(printCommand)))
+
+    m_finished = false;
+    session()->enqueueExpression(this);
+}
+
+QString OctaveExpression::internalCommand()
+{
+    QString cmd = command();
+
+    if (m_plotPending && !cmd.contains(QLatin1String("cantor_plot")) && !cmd.contains(printCommand))
     {
-        // This was a manual plot, we have to add a print command
         if (!cmd.endsWith(QLatin1Char(';')) && !cmd.endsWith(QLatin1Char(',')))
-        {
             cmd += QLatin1Char(',');
-            m_appendDot = true;
-        }
-        cmd += QLatin1String(printCommand);
-        setCommand(cmd);
-        m_appendPlotCommand = true;
+        cmd += printCommand;
     }
-    m_finished = false;
-    session()->enqueueExpression(this);
-}
 
+    cmd.replace(QLatin1String(";\n"), QLatin1String(";"));
+    cmd.replace(QLatin1Char('\n'), QLatin1Char(','));
+    cmd += QLatin1Char('\n');
+
+    return cmd;
+}
 
 void OctaveExpression::parseOutput(const QString& output)
 {
     qDebug() << "parseOutput: " << output;
 
-    if (m_appendPlotCommand)
-        removeAppendedPlotCommand();
-
     if (!output.trimmed().isEmpty())
     {
         // TODO: what about help in comment? printf with '... help ...'?
         // This must be corrected.
         if (command().contains(QLatin1String("help")))
         {
             setResult(new Cantor::HelpResult(output));
         }
         else
         {
             setResult(new Cantor::TextResult(output));
         }
     }
 
     // TODO: remove this, then there is method for notify both Highlighter and variable model about new variable
     foreach ( const QString& line, output.simplified().split(QLatin1Char('\n'), QString::SkipEmptyParts) )
     {
         if ((output.contains(QLatin1Char('='))) && !(command().startsWith(QLatin1String("help(")))
                 && !(command().contains(QLatin1String("help "))) && !(command().contains(QLatin1String("type("))))
         {
             qDebug() << line;
             // Probably a new variable
             QStringList parts = line.split(QLatin1Char('='));
             if (parts.size() >= 2)
             {
                 Cantor::DefaultVariableModel* model = dynamic_cast<Cantor::DefaultVariableModel*>(session()->variableModel());
                 if (model)
                 {
                     const QString varname = parts.first().trimmed();
                     if (varname != QLatin1String("__cantor_tmp__"))
                         model->addVariable(varname, parts.last().trimmed());
                 }
             }
         }
     }
 
     m_finished = true;
     if (!m_plotPending)
         setStatus(Done);
 }
 
 void OctaveExpression::parseError(const QString& error)
 {
     setErrorMessage(error);
     setStatus(Error);
 }
 
 void OctaveExpression::parsePlotFile(const QString& file)
 {
     qDebug() << "parsePlotFile";
     if (QFile::exists(file))
     {
         qDebug() << "OctaveExpression::parsePlotFile: " << file;
 
         setResult(new OctavePlotResult(QUrl::fromLocalFile(file)));
         setPlotPending(false);
 
         if (m_finished)
         {
             setStatus(Done);
         }
     }
 }
 
 void OctaveExpression::setPlotPending(bool plot)
 {
     m_plotPending = plot;
 }
-
-void OctaveExpression::removeAppendedPlotCommand()
-{
-    QString cmd = command();
-    cmd.remove(cmd.length()-strlen(printCommand),strlen(printCommand));
-    m_appendPlotCommand = false;
-    if (m_appendDot)
-        {
-        cmd.remove(cmd.length()-1,1);
-        m_appendDot = false;
-        }
-    setCommand(cmd);
-}
diff --git a/src/backends/octave/octaveexpression.h b/src/backends/octave/octaveexpression.h
index ed186096..761fdb36 100644
--- a/src/backends/octave/octaveexpression.h
+++ b/src/backends/octave/octaveexpression.h
@@ -1,64 +1,61 @@
 /*
     Copyright (C) 2010 Miha Čančula <miha.cancula@gmail.com>
 
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA  02110-1301, USA.
 */
 
 #ifndef OCTAVEEXPRESSION_H
 #define OCTAVEEXPRESSION_H
 
 #include <config-cantorlib.h>
 
 #include <expression.h>
 #include <QStringList>
 
 #ifdef WITH_EPS
 #include "epsresult.h"
 using OctavePlotResult = Cantor::EpsResult;
 #else
 #include "imageresult.h"
 typedef Cantor::ImageResult OctavePlotResult;
 #endif
 
 
 class OctaveExpression : public Cantor::Expression
 {
     Q_OBJECT
 
 public:
     explicit OctaveExpression(Cantor::Session*, bool internal = false);
 
     void interrupt() override;
     void evaluate() override;
+    QString internalCommand() override;
+
     void parseOutput(const QString&);
     void parseError(const QString&);
     void parsePlotFile(const QString&);
 
     void setPlotPending(bool);
 
-private:
-    void removeAppendedPlotCommand();
-
 private:
     QString m_resultString;
     bool m_plotPending;
     bool m_finished;
-    bool m_appendPlotCommand;
-    bool m_appendDot;
     QStringList m_plotCommands;
 };
 
 #endif // OCTAVEEXPRESSION_H
diff --git a/src/backends/octave/octavesession.cpp b/src/backends/octave/octavesession.cpp
index 3943ac83..343cb759 100644
--- a/src/backends/octave/octavesession.cpp
+++ b/src/backends/octave/octavesession.cpp
@@ -1,394 +1,391 @@
 /*
     Copyright (C) 2010 Miha Čančula <miha.cancula@gmail.com>
 
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA  02110-1301, USA.
 */
 
 #include "octavesession.h"
 #include "octaveexpression.h"
 #include "octavecompletionobject.h"
 #include "octavesyntaxhelpobject.h"
 #include "octavehighlighter.h"
 #include "result.h"
 #include "textresult.h"
 
 #include "settings.h"
 #include "octave-backend-config.h"
 #include "octavehighlighter.h"
 
 #include <KProcess>
 #include <KDirWatch>
 #include <KLocalizedString>
 
 #include <QTimer>
 #include <QFile>
 
 #ifndef Q_OS_WIN
 #include <signal.h>
 #endif
 
 #include <defaultvariablemodel.h>
 
 const QRegExp OctaveSession::PROMPT_UNCHANGEABLE_COMMAND = QRegExp(QLatin1String("(,|;)+"));
 
 OctaveSession::OctaveSession ( Cantor::Backend* backend ) : Session ( backend ),
 m_process(nullptr),
 m_prompt(QLatin1String("CANTOR_OCTAVE_BACKEND_PROMPT:([0-9]+)> ")),
 m_subprompt(QLatin1String("CANTOR_OCTAVE_BACKEND_SUBPROMPT:([0-9]+)> ")),
 m_previousPromptNumber(1),
 m_watch(nullptr),
 m_syntaxError(false),
 m_variableModel(new Cantor::DefaultVariableModel(this))
 {
     qDebug() << octaveScriptInstallDir;
 }
 
 void OctaveSession::login()
 {
     qDebug() << "login";
     emit loginStarted();
 
     m_process = new KProcess ( this );
     QStringList args;
     args << QLatin1String("--silent");
     args << QLatin1String("--interactive");
     args << QLatin1String("--persist");
 
     // Setting prompt and subprompt
     args << QLatin1String("--eval");
     args << QLatin1String("PS1('CANTOR_OCTAVE_BACKEND_PROMPT:\\#> ');");
     args << QLatin1String("--eval");
     args << QLatin1String("PS2('CANTOR_OCTAVE_BACKEND_SUBPROMPT:\\#> ');");
 
     // Add the cantor script directory to search path
     args << QLatin1String("--eval");
     args << QString::fromLatin1("addpath %1;").arg(octaveScriptInstallDir);
 
     if (OctaveSettings::integratePlots())
     {
         // Do not show the popup when plotting, rather only print to a file
         args << QLatin1String("--eval");
         args << QLatin1String("graphics_toolkit gnuplot;");
         args << QLatin1String("--eval");
         args << QLatin1String("set (0, \"defaultfigurevisible\",\"off\");");
     }
     else
     {
         args << QLatin1String("--eval");
         args << QLatin1String("set (0, \"defaultfigurevisible\",\"on\");");
     }
 
     // Do not show extra text in help commands
     args << QLatin1String("--eval");
     args << QLatin1String("suppress_verbose_help_message(1);");
 
     // Print the temp dir, used for plot files
     args << QLatin1String("--eval");
     args << QLatin1String("____TMP_DIR____ = tempdir");
 
     if (OctaveSettings::integratePlots())
     {
         m_watch = new KDirWatch(this);
         m_watch->setObjectName(QLatin1String("OctaveDirWatch"));
         connect (m_watch, SIGNAL(dirty(QString)), SLOT(plotFileChanged(QString)) );
     }
 
     m_process->setProgram ( OctaveSettings::path().toLocalFile(), args );
     qDebug() << "starting " << m_process->program();
     m_process->setOutputChannelMode ( KProcess::SeparateChannels );
     m_process->start();
     m_process->waitForStarted();
 
     // Got tmp dir
     bool loginFinished = false;
     QString input;
     while (!loginFinished)
     {
         m_process->waitForReadyRead();
         input += QString::fromLatin1(m_process->readAllStandardOutput());
         qDebug() << "login input: " << input;
         if (input.contains(QLatin1String("____TMP_DIR____")))
             {
                 m_tempDir = input;
                 m_tempDir.remove(0,18);
                 m_tempDir.chop(1); // isolate the tempDir's location
                 qDebug() << "Got temporary file dir:" << m_tempDir;
                 if (m_watch)
                 {
                     m_watch->addDir(m_tempDir, KDirWatch::WatchFiles);
                 }
                 loginFinished = true;
             }
     }
 
     connect ( m_process, SIGNAL (readyReadStandardOutput()), SLOT (readOutput()) );
     connect ( m_process, SIGNAL (readyReadStandardError()), SLOT (readError()) );
     connect ( m_process, SIGNAL (error(QProcess::ProcessError)), SLOT (processError()) );
 
     if(!OctaveSettings::self()->autorunScripts().isEmpty()){
         QString autorunScripts = OctaveSettings::self()->autorunScripts().join(QLatin1String("\n"));
 
         evaluateExpression(autorunScripts, OctaveExpression::DeleteOnFinish, true);
     }
 
     changeStatus(Cantor::Session::Done);
     emit loginDone();
     qDebug()<<"login done";
 }
 
 void OctaveSession::logout()
 {
     qDebug()<<"logout";
 
     if(!m_process)
         return;
 
     disconnect(m_process, nullptr, this, nullptr);
 
     // if(status()==Cantor::Session::Running)
     // TODO: terminate the running expressions first
 
     m_process->write("exit\n");
     qDebug()<<"waiting for octave to finish";
     m_process->waitForFinished();
     qDebug()<<"octave exit finished";
 
     if(m_process->state() != QProcess::NotRunning)
     {
         m_process->kill();
         qDebug()<<"octave still running, process kill enforced";
     }
 
     expressionQueue().clear();
     delete m_process;
     m_process = nullptr;
 
 
     m_tempDir.clear();
     m_output.clear();
     m_previousPromptNumber = 1;
 
     m_variableModel->clearVariables();
 
     changeStatus(Status::Disable);
 
     qDebug()<<"logout done";
 }
 
 void OctaveSession::interrupt()
 {
     if(!expressionQueue().isEmpty())
     {
         qDebug()<<"interrupting " << expressionQueue().first()->command();
         if(m_process->state() != QProcess::NotRunning)
         {
 #ifndef Q_OS_WIN
             const int pid=m_process->pid();
             kill(pid, SIGINT);
 #else
             ; //TODO: interrupt the process on windows
 #endif
         }
         expressionQueue().first()->interrupt();
         expressionQueue().removeFirst();
 
         foreach (Cantor::Expression* expression, expressionQueue())
             expression->setStatus(Cantor::Expression::Done);
         expressionQueue().clear();
 
         // Cleanup inner state and call octave prompt printing
         // If we move this code for interruption to Session, we need add function for
         // cleaning before setting Done status
         m_output.clear();
         m_process->write("\n");
 
         qDebug()<<"done interrupting";
     }
 
     changeStatus(Cantor::Session::Done);
 }
 
 void OctaveSession::processError()
 {
     qDebug() << "processError";
     emit error(m_process->errorString());
 }
 
 Cantor::Expression* OctaveSession::evaluateExpression ( const QString& command, Cantor::Expression::FinishingBehavior finishingBehavior, bool internal )
 {
     qDebug() << "evaluating: " << command;
     OctaveExpression* expression = new OctaveExpression ( this, internal);
     expression->setCommand ( command );
     expression->setFinishingBehavior ( finishingBehavior );
     expression->evaluate();
 
     return expression;
 }
 
 void OctaveSession::runFirstExpression()
 {
     OctaveExpression* expression = static_cast<OctaveExpression*>(expressionQueue().first());
     connect(expression, SIGNAL(statusChanged(Cantor::Expression::Status)), this, SLOT(currentExpressionStatusChanged(Cantor::Expression::Status)));
-    QString command = expression->command();
-    command.replace(QLatin1String(";\n"), QLatin1String(";"));
-    command.replace(QLatin1Char('\n'), QLatin1Char(','));
-    command += QLatin1Char('\n');
+    QString command = expression->internalCommand();
     expression->setStatus(Cantor::Expression::Computing);
     if (isDoNothingCommand(command))
         expression->setStatus(Cantor::Expression::Done);
     else
     {
         m_process->write ( command.toLocal8Bit() );
     }
 }
 
 void OctaveSession::readError()
 {
     qDebug() << "readError";
     QString error = QString::fromLocal8Bit(m_process->readAllStandardError());
     if (!expressionQueue().isEmpty() && !error.isEmpty())
     {
         OctaveExpression* const exp = static_cast<OctaveExpression*>(expressionQueue().first());
         if (m_syntaxError)
         {
             m_syntaxError = false;
             exp->parseError(i18n("Syntax Error"));
         }
         else
             exp->parseError(error);
 
         m_output.clear();
     }
 }
 
 void OctaveSession::readOutput()
 {
     qDebug() << "readOutput";
     while (m_process->bytesAvailable() > 0)
     {
         QString line = QString::fromLocal8Bit(m_process->readLine());
         qDebug()<<"start parsing " << "  " << line;
         if (line.contains(m_prompt))
         {
             const int promptNumber = m_prompt.cap(1).toInt();
             if (!expressionQueue().isEmpty())
             {
                 const QString& command = expressionQueue().first()->command();
                 if (m_previousPromptNumber + 1 == promptNumber || isSpecialOctaveCommand(command))
                 {
                     if (!expressionQueue().isEmpty())
                     {
                         if (command.contains(QLatin1String(" = ")) || command.contains(QLatin1String("clear")))
                         {
                             emit variablesChanged();
                         }
                         static_cast<OctaveExpression*>(expressionQueue().first())->parseOutput(m_output);
                     }
                 }
                 else
                 {
                     // Error command don't increase octave prompt number (usually, but not always)
                     readError();
                 }
             }
             m_previousPromptNumber = promptNumber;
             m_output.clear();
         }
         else if (line.contains(m_subprompt) && m_subprompt.cap(1).toInt() == m_previousPromptNumber)
         {
             // User don't write finished octave statement (for example, write 'a = [1,2, ' only), so
             // octave print subprompt and waits input finish.
             m_syntaxError = true;
             qDebug() << "subprompt catch";
             m_process->write(")]'\"\n"); // forse exit from subprompt
             m_output.clear();
         }
         else
             m_output += line;
     }
 }
 
 void OctaveSession::currentExpressionStatusChanged(Cantor::Expression::Status status)
 {
     qDebug() << "currentExpressionStatusChanged";
     switch (status)
     {
     case Cantor::Expression::Done:
     case Cantor::Expression::Error:
         expressionQueue().removeFirst();
         if (expressionQueue().isEmpty())
             changeStatus(Done);
         else
             runFirstExpression();
         break;
     default:
         break;
     }
 }
 
 void OctaveSession::plotFileChanged(const QString& filename)
 {
     if (!QFile::exists(filename) || !filename.split(QLatin1Char('/')).last().contains(QLatin1String("c-ob-")))
     {
         return;
     }
 
     if (!expressionQueue().isEmpty())
     {
         static_cast<OctaveExpression*>(expressionQueue().first())->parsePlotFile(filename);
     }
 }
 
 Cantor::CompletionObject* OctaveSession::completionFor ( const QString& cmd, int index )
 {
     return new OctaveCompletionObject ( cmd, index, this );
 }
 
 Cantor::SyntaxHelpObject* OctaveSession::syntaxHelpFor ( const QString& cmd )
 {
     return new OctaveSyntaxHelpObject ( cmd, this );
 }
 
 QSyntaxHighlighter* OctaveSession::syntaxHighlighter ( QObject* parent )
 {
     OctaveHighlighter* highlighter = new OctaveHighlighter ( parent, this );
 
     connect ( this, SIGNAL(variablesChanged()), highlighter, SLOT(updateVariables()) );
     connect ( this, SIGNAL(statusChanged(Cantor::Session::Status)), highlighter, SLOT(sessionStatusChanged(Cantor::Session::Status)) );
 
     return highlighter;
 }
 
 QAbstractItemModel* OctaveSession::variableModel()
 {
     return m_variableModel;
 }
 
 
 void OctaveSession::runSpecificCommands()
 {
     m_process->write("figure(1,'visible','off')");
 }
 
 bool OctaveSession::isDoNothingCommand(const QString& command)
 {
     return PROMPT_UNCHANGEABLE_COMMAND.exactMatch(command) || command.isEmpty();
 }
 
 bool OctaveSession::isSpecialOctaveCommand(const QString& command)
 {
     return command.contains(QLatin1String("completion_matches"));
 }