With the built-in file i/o examples that ship with LV you can't. The problem is that while the low-level file i/o functions allow you to specify a pattern that limits the listings, that input isn't propegated up to higher level functions in their example code (which you probibly shouldn't be using in deliverable code anyway). If you let me know what file i/o you need specifically I can send you a function that will do what you need...
Mike Porter email@example.com
"...after all He's not a tame lion..."
Certified Professional Instructor Certified LabVIEW Architect LabVIEW Champion