locate file in package?

[D. R. Evans]

I didn't receive any useful responses to the e-mail below, which I first
sent a few days ago (although thank you Roshan for trying).

I am still stuck on this. It's the first thing I've hit in Kubuntu that
hasn't been obvious :-( Can anyone help?

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I have just started experimenting with kubuntu, after years of working with
Mandrake/Mandriva.

I have a simple question. Suppose that I want to install a package that
will install a particular file, X. How do I determine which package will
provide the file X?

(In Mdv, this is the "find in file names" search option when installing a
package with the Mandriva Control Center -- that's the functionality I'm
trying to find in kubuntu.)

  Doc Evans