Linux command to display package description, information, version and usage (zz)

How do I display installed packages list?

If you are using rpm based distro such as Redhat/CentOS/Suse/Fedora Linux, enter:
# rpm -qa
# rpm -qa | less

If you are using apt based distro such as Debian/Ubuntu Linux, enter:
# dpkg --list

Task: Display package description and other information

If you are using rpm based distro such as Redhat/CentOS/Suse/Fedora Linux use rpm command:
rpm -qi {package-name}

For example display package description, version, vendor, build date for package called mtop, enter:
# rpm -qi mtop
Output:

Name        : mtop                         Relocations: (not relocatable) Version     : 0.6.6                             Vendor: Dag Apt Repository, http://dag.wieers.com/apt/ Release     : 1.2.el4.rf                    Build Date: Fri 20 Jan 2006 05:40:49 PM CST Install Date: Wed 07 Feb 2007 07:04:54 PM CST      Build Host: lisse.leuven.wieers.com Group       : System Environment/Base       Source RPM: mtop-0.6.6-1.2.el4.rf.src.rpm Size        : 138090                           License: GPL Signature   : DSA/SHA1, Fri 20 Jan 2006 05:48:51 PM CST, Key ID a20e52146b8d79e6 Packager    : Dag Wieers  URL         : http://mtop.sourceforge.net/ Summary     : Tool to monitor a MySQL database Description : mtop (MySQL top) monitors a MySQL database showing the queries which are taking the most amount of time to complete. Features include 'zooming' in on a process to show the complete query and 'explaining' the query optimizer information.

If you are using rpm based distro such as Debian/Ubuntu Linux use dpkg command:
dpkg -p {package-name]

For example display package description, version, and other information for package called zip, enter:
$ dpkg -p zip
Output:

Package: zip Priority: optional Section: utils Installed-Size: 248 Maintainer: Santiago Vila  Architecture: i386 Version: 2.32-1 Replaces: zip-crypt (<= 2.30-2) Depends: libc6 (>= 2.4-1) Recommends: unzip Conflicts: zip-crypt (<= 2.30-2) Size: 105640 Description: Archiver for .zip files  This is InfoZIP's zip program. It produces files that are fully  compatible with the popular PKZIP program; however, the command line  options are not identical. In other words, the end result is the same,  but the methods differ. :-)  .  This version supports encryption.