Learning and Using RPM

The RPM Package Manager (RPM) is a powerful command line driven package management system capable of installing, uninstalling, verifying, querying, and updating computer software packages. rpm.org

Why use RPM?

Red Hat initially released the Red Hat Package Manager, or RPM, to the public in 1997. Historically, a Linux user had to manually build software from source and then install the built binaries, libraries, configuration files, and man pages (documentation) by hand (or script). RPM solved that issue by simplifying the complexity of installing software on a Linux system. RPM provides a mechanism to bundle several files into a single package to distribute software which in turn is easy to maintain. It also provides easy installation, upgradability, package verification, and even has dependency evaluation. RPM packages can even be cryptographically verified using GPG for source verification. Of note is that RPM is the standard package manager for Linux Standard Base (LSB) which provides consistency to installed Linux systems across distributions. And finally in my career, RPM has been one of the components that has made government compliance easier, since it has consistency when dealing compliance standards and solid source verification since it comes directly from Red Hat. In other words it’s made my job easier.

A closer look at RPM

Regardless of your Linux ideology (Debian vs Red Hat vs Gentoo vs ???) RPM can be a great tool. Personally it’s not my first choice since I use Debian/Ubuntu at home (and Red Hat at work), but it can be very powerful nonetheless. As with any technology the key is to learn it and use it. So let’s take a little deeper look at RPM.

On the backend RPM uses Berkeley DB as a ‘Packages’ database to store all of the metadata of installed RPMs. This database is stored in /var/lib/rpm/. There are many front ends to RPM, including; yum, DNF, and Zypper, to name a few. This article will not cover front ends, however, they will be covered in a future installment. RPMs are binary files that are generally delivered with a specific name format, which is;

name-version-release.architecture.rpm

Generally RPMs have an architecture format that is commonly i386, i686, x86_64, ARM, or PPC, among others. Some packages contain a noarch extension which means it is architecture independent. RPMs can also be distributed with it’s source which usually has a .src. in the file name. Libraries can be distributed as two RPMs, one named -devel which contain development files such as headers and the other one has production ready binary files. RPM knowns about dependencies and will refuse to install until they are met. RPM will not automatically solve dependency issues like YUM.

RPMs include a package label which usually includes a software name, version (from the upstream source), package release (number of times packaged) or distribution (e.g. fc22), group, size, summary, description, and of course the architecture. To view the package label of an RPM use; rpm -qi filename.rpm.

Most of those fields in the package label are derived from the SPEC file, which is a major component in building RPMs, it’s basically the recipe. [rpmbuild] (https://fedoraproject.org/wiki/How_to_create_an_RPM_package) is the command line utility used to create a RPM. After it’s built each binary RPM contains four parts; the lead (file identification as RPM), signature (for verification of authenticity/integrity), header (metadata), and payload which is usually the file archive in cpio format. Most current versions of RPM allows the use of lzma, bzip2, or xz compression.

Using RPM

Most days when interacting with RPM I use a set of commands that I’ve committed to memory. It is those harder problems with commands that aren’t used often that get me, I usually have to hunt for those. The following is a list of RPM commands that I use frequently enough that they are nice to have in one page.

Read the RPM documentation

One of the most important things that you do is read the documentation. With these commands you can find the names of all of the man pages and a description of them as well as read any man page.

apropos rpm
man 8 rpm

Install a RPM

NOTE: You can also add the option --test to this command to make no changes to the system and simulate an install.

# rpm -ivh filename.rpm

Upgrade a RPM

NOTE: You can also add the option --test to this command to make no changes to the system and simulate an upgrade.

# rpm -Uvh filename.rpm

Remove a Package

NOTE: You can also add the option --test to this command to make no changes to the system and simulate a removal. The first option will verbosely erase a package, the second command will not verify pacakge dependencies during removal.

# rpm -eva packagename
# rpm -ev --nodeps packagename

Check RPM signature

Check all the digests and signatures in a package to verify integrity or origin.

# rpm --checksig filename.rpm

Verify all packages or a single package

Verify one or all packages are still configured properly or if changes have been made by another user or RPM.

# rpm -Va
# rpm -Vp filename.rpm

See table below

Verify package owning a file

# rpm -Vf /path/to/file

See table below

Find dependencies of a RPM or package

View a RPM or package’s dependencies.

# rpm -qRp filename.rpm
# rpm -qR packagename
# rpm -q --whatrequires filename.rpm

List all installed RPMs

Listing RPMs can be refined and match using standard Linux/Unix tools such as command pipelining and grep.

# rpm -qa

List recently installed RPMs

List the recently installed RPMs in reverse chronological order.

# rpm -qa --last

Display installed info with short description

# rpm -qi packagename
# rpm -qip filename.rpm

Find out what package a file belongs

Find out what RPM provides a certain file.

# rpm -qf /path/to/file
--or--
# rpm -q --whatprovides /path/to/file

Find documentation of installed file

# rpm -qdf /path/to/file

List all files of an installed by a package

List all files installed by a package or RPM

# rpm -ql packagename
# rpm -qlp filename.rpm
# less filename.rpm

Display scripts used in installation

View the specific scripts that are used as part of the installation and uninstallation process.

# rpm -qp --scripts filename.rpm

Query RPM database with formatting

Query the RPM database with defined ‘pretty’ formats.

# rpm -qa --queryformat '%{name}-%{version}-%{release} %{size}\n'

Display config file for RPM

View the config files for a package or RPM.

# rpm -qc packagename
# rpm -qcp filename.rpm

Display config file for command

Display the config file for a command.

# rpm -qcf /path/to/file

Find state of files in packages

Display the state of all files in an RPM or package.

# rpm -qs packagename
# rpm -qsp filename.rpm

Import RPM GPG key

Import thrid-party or custom GPG keys for package integrity verification.

# rpm --import /path/to/public/keyfile

List all imported GPG keys

List the current imported GPG keys.

# rpm -qa gpg-pubkey*

View groups

A package group is a set of packages that accomplish a specific purpose, for example, Development Tools. A unique list of groups installed can be found by querying RPM;

# rpm -qa --qf '%{group}\n' | sort -u

Table 1

Fix corrupt RPM database

Sometimes errors can occur with the RPM database that will cause issues when interacting with RPM. In this case the corrupt database need to be fixed. A very quick and easy fix is;

rm /var/lib/rpm/__db*
rpm --rebuilddb
rpmdb_verify Packages

Conclusion

RPM is a mature and powerful tool that should be understood before it is dismissed. It provides an administrator easy and quick package manipulation and can help to decrease maintence costs over time. For addtional, more in-depth, material see below.

Additional reading

https://en.m.wikipedia.org/wiki/RPM_Package_Manager http://rpm5.org/docs/rpm-guide.html http://rpm.org/documentation.html http://tldp.org/LDP/lame/LAME/linux-admin-made-easy/using-rpm.html https://www.ibm.com/developerworks/library/l-lpic1-102-5/