diff --git a/shell/main.cpp b/shell/main.cpp
index 58f6334db..b2c8b3183 100644
--- a/shell/main.cpp
+++ b/shell/main.cpp
@@ -1,175 +1,188 @@
 /*
  *  Copyright 2012 Marco Martin <mart@kde.org>
  *  Copyright 2013 Sebastian Kügler <sebas@kde.org>
  *  Copyright 2015 David Edmundson <davidedmundson@kde.org>
  *
  *  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 <QApplication>
 #include <QCommandLineParser>
 #include <QQuickWindow>
 #include <QSessionManager>
 #include <QDebug>
 #include <QMessageBox>
+#include <QDBusConnection>
+#include <QDBusMessage>
 
 #include <KAboutData>
 #include <KQuickAddons/QtQuickSettings>
 
 #include <kdbusservice.h>
 #include <klocalizedstring.h>
 #include <kcrash.h>
 #include <kworkspace.h>
 
 #include "shellcorona.h"
 #include "standaloneappcorona.h"
 #include "shellmanager.h"
 #include "coronatesthelper.h"
 
 #include <QDir>
 
 int main(int argc, char *argv[])
 {
     //Plasma scales itself to font DPI
     //on X, where we don't have compositor scaling, this generally works fine.
     //also there are bugs on older Qt, especially when it comes to fractional scaling
     //there's advantages to disabling, and (other than small context menu icons) few advantages in enabling
 
     //On wayland, it's different. Everything is simpler as all co-ordinates are in the same co-ordinate system
     //we don't have fractional scaling on the client so don't hit most the remaining bugs and
     //even if we don't use Qt scaling the compositor will try to scale us anyway so we have no choice
     if (!qEnvironmentVariableIsSet("PLASMA_USE_QT_SCALING")) {
         qunsetenv("QT_DEVICE_PIXEL_RATIO");
         QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
     } else {
         QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
     }
 
     QQuickWindow::setDefaultAlphaBuffer(true);
 
     const bool qpaVariable = qEnvironmentVariableIsSet("QT_QPA_PLATFORM");
     KWorkSpace::detectPlatform(argc, argv);
     QApplication app(argc, argv);
     if (!qpaVariable) {
         // don't leak the env variable to processes we start
         qunsetenv("QT_QPA_PLATFORM");
     }
     KLocalizedString::setApplicationDomain("plasmashell");
 
     // The executable's path is added to the library/plugin paths.
     // This does not make much sense for plasmashell.
     app.removeLibraryPath(QCoreApplication::applicationDirPath());
 
     KQuickAddons::QtQuickSettings::init();
 
     KAboutData aboutData(QStringLiteral("plasmashell"),
                          i18n("Plasma"),
                          QStringLiteral(PROJECT_VERSION),
                          i18n("Plasma Shell"),
                          KAboutLicense::GPL);
 
     KAboutData::setApplicationData(aboutData);
 
     app.setQuitOnLastWindowClosed(false);
 
     {
     QCommandLineParser cliOptions;
 
     QCommandLineOption dbgOption(QStringList() << QStringLiteral("d") <<
                                  QStringLiteral("qmljsdebugger"),
                                  i18n("Enable QML Javascript debugger"));
 
     QCommandLineOption noRespawnOption(QStringList() << QStringLiteral("n") <<
                                      QStringLiteral("no-respawn"),
                                      i18n("Do not restart plasma-shell automatically after a crash"));
 
     QCommandLineOption shellPluginOption(QStringList() << QStringLiteral("p") << QStringLiteral("shell-plugin"),
                                          i18n("Force loading the given shell plugin"),
                                          QStringLiteral("plugin"));
 
     QCommandLineOption standaloneOption(QStringList() << QStringLiteral("a") << QStringLiteral("standalone"),
                                         i18n("Load plasmashell as a standalone application, needs the shell-plugin option to be specified"));
 
+    QCommandLineOption replaceOption({QStringLiteral("replace")},
+                                 i18n("Replace an existing instance"));
 
     QCommandLineOption testOption(QStringList() << QStringLiteral("test"),
                                         i18n("Enables test mode and specifies the layout javascript file to set up the testing environment"), i18n("file"), QStringLiteral("layout.js"));
 
     cliOptions.addOption(dbgOption);
     cliOptions.addOption(noRespawnOption);
     cliOptions.addOption(shellPluginOption);
     cliOptions.addOption(standaloneOption);
     cliOptions.addOption(testOption);
+    cliOptions.addOption(replaceOption);
 
     aboutData.setupCommandLine(&cliOptions);
     cliOptions.process(app);
     aboutData.processCommandLine(&cliOptions);
 
     QGuiApplication::setFallbackSessionManagementEnabled(false);
 
     auto disableSessionManagement = [](QSessionManager &sm) {
         sm.setRestartHint(QSessionManager::RestartNever);
     };
     QObject::connect(&app, &QGuiApplication::commitDataRequest, disableSessionManagement);
     QObject::connect(&app, &QGuiApplication::saveStateRequest, disableSessionManagement);
 
     ShellManager::s_fixedShell = cliOptions.value(shellPluginOption);
 
     if (!cliOptions.isSet(noRespawnOption) && !cliOptions.isSet(testOption)) {
         KCrash::setFlags(KCrash::AutoRestart);
     }
 
     if (cliOptions.isSet(testOption)) {
         const QUrl layoutUrl = QUrl::fromUserInput(cliOptions.value(testOption), {}, QUrl::AssumeLocalFile);
         if (!layoutUrl.isLocalFile()) {
             qWarning() << "ensure the layout file is local" << layoutUrl;
             cliOptions.showHelp(1);
         }
 
         QStandardPaths::setTestModeEnabled(true);
         QDir(QStandardPaths::writableLocation(QStandardPaths::ConfigLocation)).removeRecursively();
         ShellManager::s_testModeLayout = layoutUrl.toLocalFile();
 
         qApp->setProperty("org.kde.KActivities.core.disableAutostart", true);
 
         QObject::connect(ShellManager::instance(), &ShellManager::shellChanged,
                          ShellManager::instance(),
                             [layoutUrl]() {
                                 new CoronaTestHelper(ShellManager::instance()->corona());
                             }
                         );
     }
 
     if (cliOptions.isSet(standaloneOption)) {
         if (cliOptions.isSet(shellPluginOption)) {
             ShellManager::s_standaloneOption = true;
             app.setApplicationName("plasmashell_"+cliOptions.value(shellPluginOption));
             app.setQuitOnLastWindowClosed(true);
 
             KDBusService service(KDBusService::Unique);
             //This will not leak, because corona deletes itself on window close
             new StandaloneAppCorona(cliOptions.value(shellPluginOption));
             return app.exec();
         } else {
             cliOptions.showHelp(1);
         }
     }
+
+    if (cliOptions.isSet(replaceOption)) {
+        auto message = QDBusMessage::createMethodCall(QStringLiteral("org.kde.plasmashell"),
+                                                      QStringLiteral("/MainApplication"),
+                                                      QStringLiteral("org.qtproject.Qt.QCoreApplication"),
+                                                      QStringLiteral("quit"));
+        QDBusConnection::sessionBus().call(message); //deliberately block until it's done, so we register the name after the app quits
+    }
     }
 
     KDBusService service(KDBusService::Unique);
 
     QObject::connect(QCoreApplication::instance(), &QCoreApplication::aboutToQuit, ShellManager::instance(), &QObject::deleteLater);
 
     return app.exec();
 }