dpkg -l

List all installed packages.

EXAMPLES:

dpkg returns a number of installed packages:

$ dpkg -l | wc -l
1209

ask dpkg to return only packages related to php. This will include installed and non-installed packages:

$ dpkg -l *php*

Using dpkg with grep to see only installed packages

dpkg -l | grep php

dpkg -L <package>

dpkg -L will show whether the package is installed. If the package is installed dpkg will show related files and their locations whithin the filesystem.

EXAMPLES:

$ dpkg -L ntpdate
/.
/etc
/etc/network
/etc/network/if-up.d
/etc/network/if-up.d/ntpdate
/etc/logcheck
…

$ dpkg -L php5-json
Package `php5-json’ is not installed.

dpkg -p <package>

dpkg -p will display an full information regarding to a package name provaded as an argument. The information will nclude but not limited to version, dependecies, sugested packages and more.

EXAMPLE:

$ dpkg -p dpkg
Package: dpkg
Essential: yes
Priority: required
Section: admin
Installed-Size: 7276
Origin: debian
Maintainer: Dpkg Developers <debian-dpkg@lists.debian.org>
Bugs: debbugs://bugs.debian.org
Architecture: i386
Version: 1.14.28
Replaces: manpages-de (<= 0.4-3), manpages-pl (<= 20051117-1)
Pre-Depends: libc6 (>= 2.7-1), coreutils (>= 5.93-1), lzma
Suggests: apt
Conflicts: apt (<< 0.7.7), aptitude (<< 0.4.7-1), dpkg-dev (<< 1.14.16), dpkg-iasearch (<< 0.11), sysvinit (<< 2.82-1)
Size: 2353726
Description: Debian package management system
This package provides the low-level infrastructure for handling the
installation and removal of Debian software packages.
.
For Debian package development tools, install dpkg-dev.
Homepage: http://wiki.debian.org/Teams/Dpkg

dpkg -s <package>

dpkg -s will a status of the package suplied as an argument. This is similar to dpkg -p but also inlcudes a status and config files:

EXAMPLE:

$ dpkg -s dpkg
Package: dpkg
Essential: yes
Status: install ok installed
Priority: required
Section: admin
Installed-Size: 7276
Origin: debian
Maintainer: Dpkg Developers <debian-dpkg@lists.debian.org>
Bugs: debbugs://bugs.debian.org
Architecture: i386
Version: 1.14.28
Replaces: manpages-de (<= 0.4-3), manpages-pl (<= 20051117-1)
Pre-Depends: libc6 (>= 2.7-1), coreutils (>= 5.93-1), lzma
Suggests: apt
Conflicts: apt (<< 0.7.7), aptitude (<< 0.4.7-1), dpkg-dev (<< 1.14.16), dpkg-iasearch (<< 0.11), sysvinit (<< 2.82-1)
Conffiles:
/etc/logrotate.d/dpkg 501f8c90b83c7ea180868ca82e1e82d1
/etc/dpkg/origins/debian 731423fa8ba067262f8ef37882d1e742
/etc/dpkg/dpkg.cfg f4413ffb515f8f753624ae3bb365b81b
/etc/alternatives/README 69c4ba7f08363e998e0f2e244a04f881
Description: Debian package management system
This package provides the low-level infrastructure for handling the
installation and removal of Debian software packages.
.
For Debian package development tools, install dpkg-dev.
Homepage: http://wiki.debian.org/Teams/Dpkg

dpkg -S <keyword>

this dpkg command will search and display filenames related to an installed package.

EXAMPLES:

$ dpkg -S dpkg.cfg
dpkg: /usr/share/man/hu/man5/dpkg.cfg.5.gz
dpkg: /usr/share/man/pl/man5/dpkg.cfg.5.gz
dpkg: /usr/share/man/sv/man5/dpkg.cfg.5.gz
dpkg: /etc/dpkg/dpkg.cfg
dpkg: /usr/share/man/fr/man5/dpkg.cfg.5.gz
dpkg: /usr/share/man/man5/dpkg.cfg.5.gz
dpkg: /usr/share/man/de/man5/dpkg.cfg.5.gz

$ dpkg -S ports.conf
apache2.2-common: /etc/apache2/ports.conf

dpkg -i <package>

-i option will tell dpkg to installe a package.deb. To run this command a superuser/root privilegies are required.

EXAMPLE:

# dpkg -i skype-debian_2.1.0.81-1_i386.deb

this command will install a package which is not part of the debian standard repositories. Synce dpkpg will not install a required prerequisites, dpkg may display an error that prerequisites for this package are not met.

dpkg -r <package>

dpkg will remove installed package but not its configurations. Root privilegies are required to execute this command.

EXAMPLE:

# dpkg -r apache2

this command will remove apache2 form system.

dpkg -P <package>

with -P option the dpkg command will remove and purge any configuration files related to the package.

EXAMPLE:
# dpkg -P apache2

This command will remove apache2 package from the system including its configuration files. Root permitions required.

dpkg-reconfigure <package>

dpkg-reconfigure is commadn of its own but related to the dpkg family and it is also worth to mention it here. dpkg-reconfigure will reconfigure alredy installed package in the system.

EXAMPLE:
# dpkg-reconfigure xserver-xorg

this command will reconfigure a xserver-xorg package. Root privilegies are required to execute this command.