open -n /Applications/WeChat.app
open -n /Applications/QQ.app
open: invalid option -- l Usage: open [-e] [-t] [-f] [-W] [-R] [-n] [-g] [-h] [-s <partial SDK name>][-b <bundle identifier>] [-a <application>] [-u URL] [filenames] [--args arguments] Help: Open opens files from a shell. By default, opens each file using the default application for that file. If the file is in the form of a URL, the file will be opened as a URL. Options: -a Opens with the specified application. -b Opens with the specified application bundle identifier. -e Opens with TextEdit. -t Opens with default text editor. -f Reads input from standard input and opens with TextEdit. -F --fresh Launches the app fresh, that is, without restoring windows. Saved persistent state is lost, excluding Untitled documents. -R, --reveal Selects in the Finder instead of opening. -W, --wait-apps Blocks until the used applications are closed (even if they were already running). --args All remaining arguments are passed in argv to the application's main() function instead of opened. -n, --new Open a new instance of the application even if one is already running. -j, --hide Launches the app hidden. -g, --background Does not bring the application to the foreground. -h, --header Searches header file locations for headers matching the given filenames, and opens them. -s For -h, the SDK to use; if supplied, only SDKs whose names contain the argument value are searched. Otherwise the highest versioned SDK in each platform is used. -u, --url URL Open this URL, even if it matches exactly a filepath -i, --stdin PATH Launches the application with stdin connected to PATH; defaults to /dev/null -o, --stdout PATH Launches the application with /dev/stdout connected to PATH; --stderr PATH Launches the application with /dev/stderr connected to PATH to --env VAR Add an enviroment variable to the launched process, where VAR is formatted AAA=foo or just AAA for a null string value.