Run Command

A provided run command will be executed when the blue Run button is clicked, after any provided build script. It can be used to prevent you from having to type the same command over and over in your terminal.
It can be any executable command, for example:
java {{entry}}
You'll see the {{entry}} bit is a template and is used pretty frequently in the default run commands that come with many of the sandboxes when you first launch them. It is dynamically filled with the name of the last file you opened so you can quickly swap between multiple files. You can learn more about templates here.
If at any point you'd like to revert to your starting run command, you can find your initial one on the launchpad, under Default Run Command.
You can also press Ctrl + Enter (or Cmd + Enter if you are on a Mac) to automatically run any build script and run command!