Final answer:
The command to fill a space with a pattern varies depending on the application; in graphic design software it could be a 'Fill' command with a 'Pattern' option, while in HTML5 canvas with JavaScript, you can use a repeatable image as a pattern object combined with 'fillStyle' and 'fill'.
Step-by-step explanation:
The command that allows you to fill a specified space with a specific pattern depends on the software or programming language you are using. For example, in graphic design software like Adobe Photoshop, you might use the 'Fill' command with a 'Pattern' option. In a programming context, such as using the canvas element in HTML5 with JavaScript, you could create a pattern by defining a repeatable image as a pattern object and using it to fill a shape or an entire canvas using the 'fillStyle' property and 'fill' method of the canvas context.