The rpm Command

With the rpm command, you can maintain packages, query them, build your own, and verify the ones you have. Maintaining packages involves installing new ones, upgrading to new versions, and uninstalling packages. The rpm command uses a set of options to determine what action to take. In addition, certain tasks, such as installing or querying packages, have their own options that further qualify the kind of action they take. For example, the -q option queries a package, but when combined with the -l option, it lists all the files in that package. Table 29-3 lists the set of rpm options. The syntax for the rpm command is as follows (rpm-package-name is the name of the software package you want to install):

rpm options rpm-package-name

A complete description of rpm and its capabilities is provided in the online manual:

# man rpm

Querying Information from RPM Packages and Installed Software

The -q option tells you if a package is already installed, and the -qa option displays a list of all installed packages. Piping this output to a pager utility, such as more, is best.

# rpm -qa | more

In the next example, the user checks to see if Mozilla is already installed on the system. Notice the full filename of the RPM archive is unnecessary. If the package is installed, your system has already registered its name and where it is located.

# rpm -q mozilla
mozilla-1.0.1-24

You can combine the q option with the i or l option to display information about the package. The option -qi displays information about the software, such as the version number or author (-qpi queries an uninstalled package file). The option -ql displays a listing of all the files in the software package. The --h option provides a complete list of rpm options. Common query options are shown in Table 29-4.

To display information taken directly from an RPM package, you add the p qualifier to the q options as shown in Table 29-5. The -qpi combination displays information about a specific package, and -qpl displays a listing of the files a given RPM package contains. In this case, you must specify the entire filename of the RPM package. You can avoid having to enter the entire name simply by entering a unique part of the name and using the * filename- matching character to generate the rest.

If your RPM query outputs a long list of data, like an extensive list of files, you can pipe the output to the more command to look at it screen by screen, or even redirect the output to a file.

# rpm -ql mozilla | more
# rpm -qpl emacs-21.2-18.i386.rpm  > mytemp

Installing and Updating Packages with rpm

You use the -i option to install new packages and the -U option to update currently installed packages with new versions. With an -e option, rpm uninstalls the package. If you try to use the -i option to install a newer version of an installed package, you will receive an error saying the package is already installed. When a package is installed, RPM checks its signature, using imported public keys from the software vendor. If the signature check fails, an error message is displayed, specifying NOKEY if you do not have the appropriate public key. If you want to install over an already installed package, you can force installation with the --replacepks option. Sometimes a package will include a file, such as a library, that is also installed by another package. To allow a package to overwrite the file installed by another package, you use the --replacefiles option. Many packages depend on the libraries installed by other packages. If these dependent packages are not already installed, you will first have to install them. RPM informs you of the missing dependent files and suggests packages to install. If no packages are suggested, you can use the --redhatprovides option with the missing files to search for needed packages.

The -U option also installs a package if it is not already installed, whereas the -F option will only update installed packages. If the package includes configuration files that will overwrite currently installed configuration files, it will save a copy of each current configuration file in a file ending with .rpmsave, such as /etc/mtools.conf.rpmsave. This preserves any customized configuration changes you may have made to the file. Be sure to also check for configuration compatibilities between the previous and updated versions. If you are trying to install a package that is older than the one already installed, then you need to use the --oldpackages option.

# rpm -Uvh mozilla-1.0.1-24.i386.rpm

If you are installing from a CD-ROM, you can change to the CD-ROM's RPMS directory, which holds the RPM packages (the RPMS directory may be located within a directory like RedHat on the Red Hat CD-ROM). An ls command lists all the software packages. If you know how the name of a package begins, you should include that with the ls command and an attached *. The list of packages is extensive and does not all fit on one screen. This is helpful for displaying the detailed name of the package. The following example lists most X Window System packages:

# ls x*

Installation Example

In the next example, the user first installs a new package with the -i option, and then updates a package with the -U option. Including the -v and -h options is customary. Here, -v is the verbose option that displays all files as they are installed, and -h displays a crosshatch symbol periodically to show RPM is still working. In the following example, the user installs the software package for the Balsa mail client. Notice the full filename is entered. To list the full name, you can use the ls command with the first few characters and an asterisk, ls balsa*. The rpm command with the -q option is then used to check that the software was installed. For installed packages only, the software name needs to be used—in this case, balsa-1.2.4-7.

 [root@turtle mypackages]# ls balsa*
balsa-1.2.4-7.i386.rpm
[root@turtle mypackages]# rpm -ivh balsa-1.2.4-7.i386.rpm
balsa-1.2.4-7                 ########################################
[root@turtle mypackages]# rpm -q balsa
balsa-1.2.4-7

To display information about the installed package, use -qi, and -ql displays a listing of the files a given RPM package contains.

# rpm -qi balsa
# rpm -ql balsa

If you are worried that a software package will install on your system incorrectly, you can use the test option (--test) in the debug mode (vv) to see exactly what actions RPM will take.

# rpm -ivv --test balsa-1.2.4-7.i386.rpm

Removing RPM Software Packages

To remove a software package from your system, first use rpm -q to make sure it is actually installed. Then use the -e option to uninstall it. You needn't use the full name of the installed file. You only need the name of the application. For example, if you decide you do not need Balsa, you can remove it using the -e option and the software name, as shown here:

# rpm  -e  balsa

Verifying an RPM Installation

You can use the verify option (-V) to see if any problems occurred with the installation. RPM compares the current attributes of installed files with information about them placed in the RPM database when the package was installed. If no discrepancies exist, RPM outputs nothing. Otherwise, RPM outputs a sequence of eight characters, one for each attribute, for each file in the package that fails. Those that do not differ have a period. Those that do differ have a corresponding character code, as shown in Table 29-6.

The following example verifies the ProFTPD package:

[root@turtle mypackages]# rpm -V proftpd

To compare the installed files directly with the files in an RPM package file, you use the -Vp option, much like the -qp option. To check all packages, use the -Va option as shown here:

# rpm -Va

If you want to verify a package, but you only know the name of a file in it, you can combine verify with the -f option. The following example verifies the RPM package containing the ftp command:

# rpm -Vf  /bin/ftp

Rebuilding the RPM Database

RPM maintains a record of the packages it has installed in its RPM database. You may, at times, have to rebuild this database to ensure RPM has current information on what is installed and what is not. Use the --rebuilddb option to rebuild your database file:

#  rpm --rebuilddb

To create a new RPM database, use the --initdb option. This option can be combined with --dbpath to specify a location for the new database.