Using RPM

Finding RPM Packages

Before using an RPM, you must know where to find them. An Internet search will return many RPM repositories, but if you are looking for RPM packages built by Red Hat, they can be found at the following locations:

• The official Red Hat Linux CD-ROMs

• The Red Hat Errata Page available at http://www.redhat.com/apps/support/errata/

• A Red Hat FTP Mirror Site available at http://www.redhat.com/download/mirror.html

• Red Hat Network — See Chapter 27 for more details on Red Hat Network

Installing

RPM packages typically have file names like foo-1.0-1.i386.rpm. The file name includes the package name (foo), version (1.0), release (1), and architecture (i386). Installing a package is as simple as logging in as root and typing the following command at a shell prompt:

# rpm -ivh foo-1.0-1.i386.rpm
foo                       ####################################
#

As you can see, RPM prints out the name of the package and then prints a succession of hash marks as the package is installed as a progress meter.

	Note
	Although a command like rpm -ivh foo-1.0-1.i386.rpm is commonly used to install an RPM package, you may want to consider using rpm -Uvh foo-1.0-1.i386.rpm instead. The -U option is commonly used for upgrading a package, but it will also install new packages. See the Section called Upgrading for more information about using the -U RPM option.

Installing packages is designed to be simple, but you may sometimes see errors:

# rpm -ivh foo-1.0-1.i386.rpm
foo                     package foo-1.0-1 is already installed
#

# rpm -ivh --replacepkgs foo-1.0-1.i386.rpm
foo                       ####################################
#

# rpm -ivh foo-1.0-1.i386.rpm
foo           /usr/bin/foo conflicts with file from bar-1.0-1
#

# rpm -ivh --replacefiles foo-1.0-1.i386.rpm
foo                       ####################################
#

# rpm -ivh foo-1.0-1.i386.rpm
failed dependencies:
        bar is needed by foo-1.0-1
#

Uninstalling

Uninstalling a package is just as simple as installing one. Type the following command at a shell prompt:

# rpm -e foo
#

	Note
	Notice that we used the package name foo, not the name of the original package file foo-1.0-1.i386.rpm. To uninstall a package, you will need to replace foo with the actual package name of the original package.

You can encounter a dependency error when uninstalling a package if another installed package depends on the one you are trying to remove. For example:

# rpm -e foo
removing these packages would break dependencies:
        foo is needed by bar-1.0-1
#

To cause RPM to ignore this error and uninstall the package anyway (which is also a bad idea since the package that depends on it will probably fail to work properly), use the --nodeps option.

Upgrading

Upgrading a package is similar to installing one. Type the following command at a shell prompt:

# rpm -Uvh foo-2.0-1.i386.rpm
foo                       ####################################
#

What you do not see above is that RPM automatically uninstalled any old versions of the foo package. In fact, you may want to always use -U to install packages, since it will work even when there are no previous versions of the package installed.

Since RPM performs intelligent upgrading of packages with configuration files, you may see a message like the following:

saving /etc/foo.conf as /etc/foo.conf.rpmsave

This message means that your changes to the configuration file may not be "forward compatible" with the new configuration file in the package, so RPM saved your original file, and installed a new one. You should investigate the differences between the two configuration files and resolve them as soon as possible, to ensure that your system continues to function properly.

Upgrading is really a combination of uninstalling and installing, so during an RPM upgrade you can encounter uninstalling and installing errors, plus one more. If RPM thinks you are trying to upgrade to a package with an older version number, you will see:

# rpm -Uvh foo-1.0-1.i386.rpm
foo    package foo-2.0-1 (which is newer) is already installed
#

To cause RPM to "upgrade" anyway, use the --oldpackage option:

# rpm -Uvh --oldpackage foo-1.0-1.i386.rpm
foo                       ####################################
#

Freshening

Freshening a package is similar to upgrading one. Type the following command at a shell prompt:

# rpm -Fvh foo-1.2-1.i386.rpm
foo                       ####################################
#

RPM's freshen option checks the versions of the packages specified on the command line against the versions of packages that have already been installed on your system. When a newer version of an already-installed package is processed by RPM's freshen option, it will be upgraded to the newer version. However, RPM's freshen option will not install a package if no previously-installed package of the same name exists. This differs from RPM's upgrade option, as an upgrade will install packages, whether or not an older version of the package was already installed.

RPM's freshen option works for single packages or a group of packages. If you have just downloaded a large number of different packages, and you only want to upgrade those packages that are already installed on your system, freshening will do the job. If you use freshening, you will not have to deleting any unwanted packages from the group that you downloaded before using RPM.

In this case, you can simply issue the following command:

# rpm -Fvh *.rpm

RPM will automatically upgrade only those packages that are already installed.

Querying

Use the rpm -q command to query the database of installed packages. The rpm -q foo command will print the package name, version, and release number of the installed package foo:

# rpm -q foo
foo-2.0-1
#

	Note
	Notice that we used the package name foo. To query a package, you will need to replace foo with the actual package name.

Instead of specifying the package name, you can use the following options with -q to specify the package(s) you want to query. These are called Package Specification Options.

• -a queries all currently installed packages.

• -f <file> will query the package which owns <file>. When specifying a file, you must specify the full path of the file (for example, /usr/bin/ls).

• -p <packagefile> queries the package <packagefile>.

There are a number of ways to specify what information to display about queried packages. The following options are used to select the type of information for which you are searching. These are called Information Selection Options.

• -i displays package information including name, description, release, size, build date, install date, vendor, and other miscellaneous information.

• -l displays the list of files that the package contains.

• -s displays the state of all the files in the package.

• -d displays a list of files marked as documentation (man pages, info pages, READMEs, etc.).

• -c displays a list of files marked as configuration files. These are the files you change after installation to adapt the package to your system (for example, sendmail.cf, passwd, inittab, etc.).

For the options that display lists of files, you can add -v to the command to display the lists in a familiar ls -l format.

Verifying

Verifying a package compares information about files installed from a package with the same information from the original package. Among other things, verifying compares the size, MD5 sum, permissions, type, owner, and group of each file.

The command rpm -V verifies a package. You can use any of the Package Selection Options listed for querying to specify the packages you wish to verify. A simple use of verifying is rpm -V foo, which verifies that all the files in the foo package are as they were when they were originally installed. For example:

• To verify a package containing a particular file:

  rpm -Vf /bin/vi

• To verify ALL installed packages:

  rpm -Va

• To verify an installed package against an RPM package file:

  rpm -Vp foo-1.0-1.i386.rpm

  This command can be useful if you suspect that your RPM databases are corrupt.

If everything verified properly, there will be no output. If there are any discrepancies they will be displayed. The format of the output is a string of eight characters (a c denotes a configuration file) and then the file name. Each of the eight characters denotes the result of a comparison of one attribute of the file to the value of that attribute recorded in the RPM database. A single . (a period) means the test passed. The following characters denote failure of certain tests:

• 5 — MD5 checksum

• S — file size

• L — symbolic link

• T — file modification time

• D — device

• U — user

• G — group

• M — mode (includes permissions and file type)

• ? — unreadable file

If you see any output, use your best judgment to determine if you should remove or reinstall the package, or fix the problem in another way.