If you want an icon you can double click on your desktop, you can put you command in a file with the extension “.command” and mark it as executable. Double clicking it will run the content as a shell script in Terminal.
If you want something that can be put into the Dock, use the Script Editor application that comes with macOS to create a new AppleScript script. Type do shell script "<firefox command here>" then find Export in the menu. Instead of Script, choose export to Application and check Run Only. This will give you an application you can put in the Dock.
If you want to use Shortcuts, you can use the Run Shell Script action in Shortcuts too.
Finally, if you want something that opens multiple firefoxes at once, chain multiple firefox invocations together on one line separated by an ampersand. There is an option you have to use (–new-instance I think?) to make Firefox actually start a complete new instance.
On Mac:
If you want an icon you can double click on your desktop, you can put you command in a file with the extension “.command” and mark it as executable. Double clicking it will run the content as a shell script in Terminal.
If you want something that can be put into the Dock, use the Script Editor application that comes with macOS to create a new AppleScript script. Type
do shell script "<firefox command here>"then find Export in the menu. Instead of Script, choose export to Application and check Run Only. This will give you an application you can put in the Dock.If you want to use Shortcuts, you can use the Run Shell Script action in Shortcuts too.
Finally, if you want something that opens multiple firefoxes at once, chain multiple firefox invocations together on one line separated by an ampersand. There is an option you have to use (–new-instance I think?) to make Firefox actually start a complete new instance.