A Few Handy Queries

Below are some examples of situations you might find yourself in, and ways you can use RPM to get the information you need. Keep in mind that these are just examples. Don't be afraid to experiment!

Finding Config Files Based on a Program Name

You're setting up a new system, and you'd like to implement some system-wide aliases for people using the Bourne Again SHell, bash. The problem is you just can't remember the name of the system-wide initialization file used by bash, or where it resides:
# rpm -qcf /bin/bash
/etc/bashrc
#
          
Rather than spending time trying to hunt down the file, RPM finds it for you in seconds.

Learning More About an Uninstalled Package

Practically any option can be combined with -qp to extract information from a .rpm file. Let's say you have an unknown .rpm file, and you'd like to know a bit more before installing it:
# rpm -qpil foo.bar
Name        : rpm                  Distribution: Red Hat Linux Vanderbilt
Version     : 2.3                        Vendor: Red Hat Software
Release     : 1                      Build Date: Tue Dec 24 09:07:59 1996
Install date: (none)                 Build Host: porky.redhat.com
Group       : Utilities/System       Source RPM: rpm-2.3-1.src.rpm
Size        : 631157
Summary     : Red Hat Package Manager
Description :
RPM is a powerful package manager, which can be used to build, install,
query, verify, update, and uninstall individual software packages. A
package consists of an archive of files, and package information,
including name, version, and description.
/bin/rpm
/usr/bin/find-provides
/usr/bin/find-requires
/usr/bin/gendiff
/usr/bin/rpm2cpio
/usr/doc/rpm-2.3-1
…
/usr/src/redhat/SOURCES
/usr/src/redhat/SPECS
/usr/src/redhat/SRPMS
# 
          

By displaying the package information, we know that we have a package file containing RPM version 2.3. We can then peruse the file list, and see exactly what it would install before installing it.

Finding Documentation for a Specific Package

Picking on bash some more, you realize that your knowledge of the software is lacking. You'd like to see when it was installed on your system, and what documentation is available for it:
# rpm -qid bash
Name        :bash                   Distribution: Red Hat Linux (Picasso)
Version     :1.14.6                       Vendor: Red Hat Software
Release     :2                        Build Date: Sun Feb 25 13:59:26 1996
Install date:Mon May 13 12:47:22 1996 Build Host: porky.redhat.com
Group       :Shells                   Source RPM: bash-1.14.6-2.src.rpm
Size        :486557
Description :GNU Bourne Again Shell (bash)
/usr/doc/bash-1.14.6-2
/usr/doc/bash-1.14.6-2/NEWS
/usr/doc/bash-1.14.6-2/README
/usr/doc/bash-1.14.6-2/RELEASE
/usr/info/bash.info.gz
/usr/man/man1/bash.1
#
          
You never realized that there could be so much documentation for a shell!

Finding Similar Packages

Looking at bash's information, we see that it belongs to the group "Shells". You're not sure what other shell packages are installed on your system. If you can find other packages in the "Shells" group, you'll have found the other installed shells:
# rpm -qa --queryformat '%10{NAME} %20{GROUP}\n' | grep -i shells
       ash               Shells
      bash               Shells
       csh               Shells
        mc               Shells
      tcsh               Shells
#
          
Now you can query each of these packages, and learn more about them, too. [1]

Finding Recently Installed Packages, Part I

You remember installing a new package a few days ago. All you know for certain is that the package installed a new command in the /bin directory. Let's try to find the package:
# find /bin -type f -mtime -14 | rpm -qF
rpm-2.3-1
#
          
Looks like RPM version 2.3 was installed sometime in the last two weeks.

Finding Recently Installed Packages, Part II

Another way to see which packages were recently installed is to use the --queryformat option:
# rpm -qa --queryformat '%{installtime} %{name}-%{version}-%{release} %{installtime:date}\n' | sort -nr +1 | sed -e 's/^[^ ]* //'
rpm-devel-2.3-1 Thu Dec 26 23:02:05 1996
rpm-2.3-1 Thu Dec 26 23:01:51 1996
pgp-2.6.3usa-2 Tue Oct 22 19:39:09 1996
…
pamconfig-0.50-5 Tue Oct 15 17:23:22 1996
setup-1.5-1 Tue Oct 15 17:23:21 1996
#
          
By having RPM include the installation time in numeric form, it was simple to sort the packages and then use sed to remove the user-unfriendly numeric time.

Finding the Largest Installed Packages

Let's say that you're running low on disk space, and you'd like to see what packages you have installed, along with the amount of space each package takes up. You'd also like to see the largest packages first, so you can get back as much disk space as possible:
# rpm -qa --queryformat '%{name-%{version}-%{release} %{size}\n' | sort -nr +1
kernel-source-2.0.18-5  20608472
tetex-0.3.4-3  19757371
emacs-el-19.34-1  12259914
…
rootfiles-1.3-1  3494
mkinitrd-1.0-1  1898
redhat-release-4.0-1  22
#
          
If you don't build custom kernels, or use TeX, it's easy to see how much space could be reclaimed by removing those packages.

Notes

[1]

Did you see this example and say to yourself, "Hey, they could've used the -g option to query for that group directly"? If you did, you've been paying attention. This is a more general way of searching the RPM database for information: we just happened to search by group in this example.