As the gang has already pointed out, the documentation for split dispells the mystery. If you're trying to eliminate all empty fields, the grep trick that BrowserUk illustrated is a good solution. But if you're only trying to eliminate one or two (or a few) leading empty fields, you can do this:

shift @nseg until length $nseg[0];
[download]

...of course that's not going to help if @nseg contains nothing but empty fields. ;)