From MEPIS Documentation Wiki
Run Command is an input box that you can use to enter commands without opening a console program.
To get the "run command" input box press Alt+F2 key combination (key combination might be different if you changed the default keyboard shortcuts). Another way to call it is by selecting "run command" from K Menu or from the menu that you obtain when you right-click on the desktop.
It is preferable to use konsole instead of "run command" if the program that you want to start doesn't have a GUI or if the output of the program goes to the terminal and you need to see it.