SingleApplication
                                Replacement of QtSingleApplication for Qt 5 and Qt 6 with support for inter-instance communication.
                            
                        How to download and setup SingleApplication
Open terminal and run command
                                            git clone https://github.com/itay-grudev/SingleApplication.git
                                        
                                        git clone is used to create a copy or clone of SingleApplication repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with SingleApplication https://github.com/itay-grudev/SingleApplication/archive/master.zip
Or simply clone SingleApplication with SSH
                                            [email protected]:itay-grudev/SingleApplication.git                                    
                                    If you have some problems with SingleApplication
You may open issue on SingleApplication support forum (system) here: https://github.com/itay-grudev/SingleApplication/issuesSimilar to SingleApplication repositories
Here you may see SingleApplication alternatives and analogs
electron CNTK aws-doc-sdk-examples awesome-cpp open-source-mac-os-apps textmate xbmc infer pragmatapro Sophus symengine openage ChakraCore OpenRCT2 openpose x64dbg tiny-dnn cpr ardb kakoune tinyrenderer finalcut poco tiled liteide qt qutebrowser MuseScore mapbox-gl-native qTox