How do I find the package that provides a file?

Question

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.

Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?

Answer 1

You can use dpkg command to find out which package owns a file:

dpkg -S /bin/ls

You can either search with a full path or with just the filename.

If you wish to search for files not yet installed on your computer, you can use the Ubuntu Packages Search

Answer 2

The apt-file command can do this for you from the command line. I use it frequently when building packages from source. For files provided by packages that are already installed on your system, apt-cache is another choice.

However a much friendlier way is to use the Ubuntu Packages Search website. They have an option to "search the contents of packages" for a specific filename.

Answer 3

There's also apt-file for looking up files in packages that aren't installed.

Answer 4

You can search the contents of packages included in the various Ubuntu releases on the Ubuntu Packages website. Look under the heading "Search the contents of packages".

For example, here are the search results for libnss3.so in lucid (10.04):

http://packages.ubuntu.com/search?searchon=contents&keywords=libnss3.so&mode=exactfilename&suite=lucid&arch=any

Answer 5

One reason you might have to do this is if you are compiling software which there already is an ubuntu package, you can run apt-get build-dep $PACKAGENAME. That will install all packages you need to compile $PACKAGENAME.