Which package did a particular file come from

I sometimes find myself trying to figure out which package a particular file came from. It's usually a binary I want available on a different Debian-based machine and an aptitude search binaryname isn't returning anything.

I think I've done this a few times before with dpkg-query commands of some kind but it was never simple enough to remember. I Googled the problem again today and came up with an article introducing dlocate. It just has to be installed (its package is helpfully called "dlocate") and then to find out where pdfimages came from I just have to type dlocate pdfimages.

But that gave me three lines of output -- I have a python script called pdfimages.py which came from python-reportlab, a gzipped manpage which came with poppler-utils and the binary I was actually looking for, also from poppler-utils. So I could have made the query more specific by giving a full path to the file -- quickest way with a binary is of course using which: dlocate $(which pdfimages).