Linux command to display package description, information, version and usage

Q. I’m using Linux since last one year but I’m not able to find out command which will display package description, usage, copyright information etc. Can you tell us the Linux package description command name?

A. Different Linux distribution use different command to display package information. Generally you use rpm or apt-get/dpkg commands for package management.

Task: 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.