How many times have you noticed a file sitting in a directory and wondered… where did this file come from?  Or you are trying to tell a friend how to use a utility but he doesn't have it installed, and you can't remember what package you installed to get it.

Sure, you can head over to google, but don't you always wonder how those people know? It's simple, install the dlocate utility, which is a faster alternative to dpkg for this type of query.

sudo apt-get install dlocate

You can use the command with the syntax 'dlocate <filename>', which will give you this output:

$ dlocate flac

libxine1: /usr/lib/xine/plugins/1.1.4/xineplug_flac.so
libtunepimp5: /usr/lib/tunepimp/plugins/flac.tpp
gstreamer0.10-plugins-good: /usr/lib/gstreamer-0.10/libgstflac.so
flac: /.
flac: /usr
flac: /usr/bin
flac: /usr/bin/flac
—– trimmed ——

That's a lot of output! You can see that there are a lot of filenames that partially match. Better to pass the full path to the filename. In this case, you can use 'which flac' to determine which flac command you are using, and then pass the full path to dlocate.

$ which flac

/usr/bin/flac

$ dlocate /usr/bin/flac

flac: /usr/bin/flac

Now we know that the flac command is found in the package called "flac". (Yes, this example was very simple) You could even get more creative (use the character next to the 1 key, not a single quote)

$ dlocate `which flac`

flac: /usr/bin/flac

If you don't feel like installing another utility, you can use the 'dpkg -S <filename>'  command that is built in, but the output isn't nearly as fast or organized. Just make sure you pass the full path of the file to either utility and you should get good results.