RPM provides a powerful tool for managing software installed on a system. With a single command, an entire application can be installed on the system in a ready-to-run configuration. With a different command, the entire application can be removed without having manually to track down all of the associated files scattered throughout the hard drive. For RPM to work, however, the software being managed must be packaged in the proper RPM format. RPM packages can be easily prepared if necessary, but you can save time by using the wide variety of software already available in the RPM format. The only trick to using this RPM-packaged software is finding it.
As you start to search for RPM packages on the Internet, you’ll find thousands of packages available. Many of these packages are built specifically for various Linux distributions, such as Conectiva, SUSE, Red Hat, or Mandrake. In many cases, the Linux distribution won’t matter, but in general it's best to download packages built for your version of Linux, such as Red Hat.
Although the examples in this book assume Red Hat Linux as a base, just about everything applies to all versions of Linux that use the RPM system, unless noted otherwise.
Internet search engines are popular, but they aren’t very helpful for finding RPM packages, especially because lots of Web pages have the term rpm (including those covering revolutions per minute). A more efficient approach is to use one of the RPM-specific Internet search tools such as rpmfind.
7.1.1. rpmfind and rpm2html
One popular free tool for locating RPMs is rpmfind, written by Daniel Veillard. This tool provides a command-line utility that can search for packages by name or description, displaying or optionally downloading any matching packages it finds. It can even provide a list of the dependencies that those matching packages require to run and can download those required dependencies as well.
When searching for packages, rpmfind can search both the software already installed on the local system and remote databases, including the databases located at http://rpmfind.net/.
Note
The databases at http://rpmfind.net/ are, in turn, created by another utility: rpm2html. Both are covered in the section following.
Commonly, rpmfind is used to search for packages by name, though it can be used to search package descriptions for key words. For example, I might want to find new e-mail clients to install on my system. I happen to know that one popular Linux e-mail client is Ximian’s evolution, so I search for that.
The basic syntax for rpmfind follows:
rpmfind package_name
For example, to search for evolution, use a command like the following:
$ rpmfind evolution
Resource evolution already installed
$
Before accessing the Internet, rpmfind searches my local system and finds that I already have evolution installed, so it does not even bother searching for copies to download. It looks like I’m forgetful, not remembering that I already have evolution installed. At this point, I might realize that I already have the software I need, or I might decide to search for a similar application, such as exmh, another popular Unix e-mail client.
To search for exmh (which in this example has not been installed), use a command like the following:
$ rpmfind exmh
Installing exmh will require 7301 KBytes
### To Transfer:
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//nmh-1.0.4-9.i3
86.rpm
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//exmh-2.4-2.noarch.rpm
Do you want to download these files to /tmp [Y/n/a/i] ? : a
transferring
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//nmh-1.0.4-9.i386.rpm
saving to /tmp/nmh-1.0.4-9.i386.rpm
transferring
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//exmh-2.4-2.noarch.rpm
saving to /tmp/exmh-2.4-2.noarch.rpm
rpm -U /tmp/nmh-1.0.4-9.i386.rpm /tmp/exmh-2.4-2.noarch.rpm
$
Here, rpmfind searches my local system for exmh. Since exmh is not installed there, rpmfind searches the databases at http://rpmfind.net/ and does two things: it finds exmh, and it learns that exmh depends upon another package: nmh. After double-checking and learning that nmh is not installed on my local system, rpmfind gives me a choice regarding whether I should download both of those packages; rpmfind gives me four possible answers:
Do you want to download these files to /tmp [Y/n/a/i] ? : a
My possible answers were:
YYes, do download the files.
NNo, do not download the files.
AGet all. By default, run in Automatic mode, trying to upgrade packages after they are downloaded
IInstall packages after download.
Note
Any user can download packages, but usually only the root user can install packages. Unless you are logged in as root, rpmfind will likely fail to install the downloaded RPMs.
Because I select the "a" answer, rpmfind downloads all necessary packages to /tmp and tries to upgrade the packages automatically by running the following command:
rpm -U /tmp/nmh-1.0.4-9.i386.rpm /tmp/exmh-2.4-2.noarch.rpm
In this case, the rpm -U command silently fails, since I am not running it as root and do not have permission to install software.
If the name of a package is unknown, rpmfind also supports searching by keywords. The --apropos pattern option tells rpmfind to search through all package descriptions in the databases for the pattern. If I do not know the names of any e-mail clients, I might use this code for my search:
$ rpmfind --apropos "mail client"
Searching the RPM catalog for mail client ...
1:
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//netscape-communicator-4.78-2.i386.rpm
netscape-communicator : A Web browser, news reader and e-mail client.
2:
ftp://ftp.redhat.com/pub/redhat/linux/7.2/en/os/i386/RedHat/RPMS//sylpheed-0.5.0-3.i386.rpm
sylpheed : A GTK+ based, lightweight, and fast email client.
<snip>
364: ftp://ftp.pld.org.pl/PLD-1.0/dists/ra/PLD/SRPMS/SRPMS/sylpheed-0.7.4-1.src.rpm
sylpheed : GTK+ based fast e-mail client
From my search, rpmfind returns the following output (with most of the entries edited out for space):
Found 364 packages related to mail client
$
With this command, rpmfind connects to the databases at http://rpmfind.net/ and returns the location of all packages whose description contains the text “mail client”. Notice that 364 packages are found; there are lots of e-mail clients available for Linux! That number, however, is slightly misleading. Some of the packages found are prepared for the distribution I am running (Red Hat Linux version 7.2), but others are not. Result #364, for example, appears to be the Polish(ed) Linux Distribution 1.0 package of sylpheed, the same software offered to me packaged for my Red Hat Linux version 7.2 system in Result #2.
Warning
Use caution when working with rpmfind. By default, it connects to the databases on the server http://rpmfind.net/ and queries them. These databases are indexes of all RPM-based distributions, and of all versions of each RPM-based distribution, and of all architectures, and of both source and binary RPMs for all these distributions!
To help you avoid being overwhelmed with results (such as the 364 results I obtain when I search for “mail client”), options are available to fine-tune rpmfind’s searches in various ways. Common options are presented in Table 8-1.
Table 8-1SEARCH OPTIONS FOR rpmfind
The rpmfind databases that rpmfind searches are created using the utility rpm2html. If you desire, rpm2html can be used to set up a local mirror of the databases at rpmfind.net or to make a custom database of locally available RPMs for in-house use.
rpm2html
The rpm2html utility generates HTML Web pages that describe RPM packages. Very simple in concept, rpm2html has proven very useful over the years.
With rpm2html, each package is displayed as a single HTML page that describes the package using information much like that returned by the rpm -qi command, covered in
Chapter 3, Using RPM . The HTML page also lists the capabilities the package requires and those it provides. This shows the needed dependency information. Finally, the page includes a download link to download the RPM file.
All packages of the same name, such as the exmh e-mail client, are collected on summary pages. The summary page tries to list all RPMs for all Linux distributions that provide the given package. For exmh, for example, the database as of this writing includes 71 versions of the exmh package, for Conectiva Linux, Mandrake Linux, Yellow Dog PowerPC Linux, and so on. The summary page also links to the URL in the RPMs that is listed as the home page for the application.
Used together with its database, rpm2html provides a powerful RPM-centric search engine. You can find more on rpm2html at rpmfind.net/linux/rpm2html/ or just access an RPM search site such as rpmfind.net.
In addition to rpm2html, the program pdbv creates a set of cross-linked HTML files that list the packages on your system. Pdbv doesn’t support searching and wasn’t built as a front end for search sites, so it is simpler than rpm2html. Instead, pdbv just creates a set of HTML pages that list data that you can query with the rpm command, including the package descriptions, the capabilities required and provided, as well as all the files in the package.
The primary advantage of pdbv is that it runs relatively quickly to provide you a snapshot of your system.
