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RPM

An RPM package is a cpio package with some additional structures.
Find the package that contains a given file: 
$ rpm -qf /usr/bin/man
man-db-2.6.7.1-16.fc21.x86_64
Find package's upstream URL: 
$ rpm -qi man-db | grep -i url
URL         : http://www.nongnu.org/man-db/
Apparently, the Debian equivalents are 
$ dpkg -S /usr/bin/man
$ apt-cache show man-db | grep Homepage

View files in a of a package

The following command lists the files (but not the installaion scripts) of a package: 
rpm -ql xyz.rpm

Extracting data from an RPM

RedHat provides the rpm2cpio utility which extracts a cpio from an rpm package.
alien-pkg-convert is a Perl utility than can convert RPM packges various other package formats (such as .deb)
Here's a lightweight implementation of rpm2cpio for Python.

Extract ONE file from an rpm package

The following command extracts the file /opt/abc/def.txt from xyz.rpm to /tmp/def.txt.
Note: the path in the command is specified relatively (i. e. with a leading ./): 
$ rpm2cpio xyz.rpm | cpio -iv --to-stdout ./opt/abc/def.txt > /tmp/def.txt

See also

rpm2cpio.sh is able to create a cpio file from an .rpm file.
The RPM database is stored in /var/lib/rpm.
/etc/rpm
/etc/pki/rpm-gpg/
/var/lib/rpm
package manager

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