how to check if a package is installed or not In Ubuntu ?

If you’re managing Debian or Ubuntu servers, probably, you may use dpkg or apt-get commands often. These two commands are used to install, remove, update packages.

In this brief tutorial, let us see how to check if a package is installed or not in DEB based systems.

To check whether a particular package for example firefox, is installed or not using command:

dpkg -s firefox

Sample output:

 Package: firefox

 Status: install ok installed

 Priority: optional

 Section: web

 Installed-Size: 93339

 Maintainer: Ubuntu Mozilla Team <ubuntu-mozillateam@lists.ubuntu.com>

 Architecture: amd64

 Version: 35.0+build3-0ubuntu0.14.04.2

 Replaces: kubuntu-firefox-installer

 Provides: gnome-www-browser, iceweasel, www-browser

 Depends: lsb-release, libasound2 (>= 1.0.16), libatk1.0-0 (>= 1.12.4), libc6 (>= 2.17), libcairo2 (>= 1.2.4), libdbus-1-3 (>= 1.0.2), libdbus-glib-1-2 (>= 0.78), libfontconfig1 (>= 2.9.0), libfreetype6 (>= 2.2.1), libgcc1 (>= 1:4.1.1), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.37.3), libgtk2.0-0 (>= 2.24.0), libpango-1.0-0 (>= 1.22.0), libpangocairo-1.0-0 (>= 1.14.0), libstartup-notification0 (>= 0.8), libstdc++6 (>= 4.6), libx11-6, libxcomposite1 (>= 1:0.3-1), libxdamage1 (>= 1:1.1), libxext6, libxfixes3, libxrender1, libxt6

 Recommends: xul-ext-ubufox, libcanberra0, libdbusmenu-glib4, libdbusmenu-gtk4

 Suggests: ttf-lyx

 Conffiles:

 /etc/firefox/syspref.js 09e457e65435a1a043521f2bd19cd2a1

 /etc/apport/blacklist.d/firefox ee63264f847e671832d42255912ce144

 /etc/apport/native-origins.d/firefox 7c26b75c7c2b715c89cc6d85338252a4

 /etc/apparmor.d/usr.bin.firefox f54f7a43361c7ecfa3874abca2f292cf

 Description: Safe and easy web browser from Mozilla

 Firefox delivers safe, easy web browsing. A familiar user interface,

 enhanced security features including protection from online identity theft,

 and integrated search let you get the most out of the web.

 Xul-Appid: {ec8030f7-c20a-464f-9b0e-13a3a9e97384}

As you see in the above output, the firefox is installed.

Also, you can do the same using dpkg-query command. This command displays the decent output, and of course, you can wild cards too.

dpkg-query -l firefox

Sample output:

Desired=Unknown/Install/Remove/Purge/Hold

| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend

|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)

||/ Name                                 Version                 Architecture            Description

+++-====================================-=======================-=======================-=============================================================================

ii  firefox                              35.0+build3-0ubuntu0.14 amd64                   Safe and easy web browser from Mozilla

To list all installed package in your system, enter the following command

dpkg --get-selections

Sample output:

abiword                        install

abiword-common                    install

accountsservice                    install

acl                        install

adduser                        install

alsa-base                    install

alsa-utils                    install

anacron                        install

app-install-data                install

apparmor                    install

.

.

.

zeitgeist                    install

zeitgeist-core                    install

zeitgeist-datahub                install

zenity                        install

zenity-common                    install

zip                        install

zlib1g:amd64                    install

zlib1g:i386                    install

The above might be very long depending upon the number of packages you have installed on your system.

You can also filter through grep to get results for the exact package you need. For example, I want to see which gcc packages are already installed on my system using dpkg command:

dpkg --get-selections | grep gcc

Sample output:

gcc                        install

gcc-4.8                        install

gcc-4.8-base:amd64                install

gcc-4.8-base:i386                install

gcc-4.9-base:amd64                install

gcc-4.9-base:i386                install

libgcc-4.8-dev:amd64                install

libgcc1:amd64                    install

libgcc1:i386                    install

Additionally, you can find location of the files within a package using the parameter “-L”.

dpkg -L gcc-4.8

Sample output:

/.

/usr

/usr/share

/usr/share/doc

/usr/share/doc/gcc-4.8-base

/usr/share/doc/gcc-4.8-base/README.Bugs

/usr/share/doc/gcc-4.8-base/NEWS.html

/usr/share/doc/gcc-4.8-base/quadmath

/usr/share/doc/gcc-4.8-base/quadmath/changelog.gz

/usr/share/doc/gcc-4.8-base/gcc

.

.

.

/usr/bin/x86_64-linux-gnu-gcc-4.8

/usr/bin/x86_64-linux-gnu-gcc-ar-4.8

/usr/bin/x86_64-linux-gnu-gcov-4.8