Query installed packages on Ubuntu

Ubuntu uses debian packages, not RPMs so yum isn't relevant.

List all packages:
dpkg-query -l

Display summary info for a package:
dpkg-query -s package_name

Display files installed by a package:
dpkg-query -L package_name

Working with RPMs

Use -q to query:

    rpm -qi package_name # display info about the specified package

    rpm -ql package_name # list all the files in the specified package

    rpm -qa # list all installed packages

Add -p if you're querying an RPM file, omit it if you're querying an installed package.

Who created an RPM?

You can get a clue by finding out the name of the host on which it was built:

    rpm -pqi foo.rpm

Extract an RPM file

How to see what's in an RPM file:

rpm2cpio /path/to/file.rpm | cpio -i --make-directories

Thanks to askubuntu.com

To where has yum installed a package?

Yum works with RPMs:

rpm -ql packagename