How to Check If Package Is Installed in CentOS/RHEL/Ubuntu Linux

This post will guide you how to check if package is installed on CentOS/RHEL/Ubuntu Linux. How to find if a package is installed or not in CentOS/RHEL/Ubuntu Linux system. How to List all installed packages in your Linux operating system.

Check If Package Is Installed in Linux

Before installed one package, you need to check if this package is installed already or not in your Linux system. So How to check the installed packages in the different Linux distribution. Let’s see the following introduction.

For CentOS/RHEL Linux

If you are using CentOS/RHEL Linux, and you want to check if a specific package is installed or not, you can use the rpm command with -qa option to achieve the result. Type the following command to check if httpd package is installed or not:

$ rpm -qa | grep httpd

Outputs:

[root@osetc_test ~]# rpm -qa | grep httpd
httpd-tools-2.2.15-59.el6.centos.x86_64
httpd-tools-2.2.15-60.el6.centos.6.x86_64
httpd-2.2.15-60.el6.centos.6.x86_64

From the above outputs, you can know that the httpd package has been installed in your system, and the installed version of httpd is 2.2.15-60.

You can also use the yum command to achieve the same result, type:

$ yum list installed httpd

Outputs:

[root@osetc_test ~]# yum list installed httpd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.sonic.net
* epel: mirror.sjc02.svwh.net
* extras: mirror.fileplanet.com
* updates: mirror.sjc02.svwh.net
Installed Packages
httpd.x86_64 2.2.15-60.el6.centos.6 @updates
[root@osetc_test ~]#

List All Installed Packages

If you want only to list all installed packages in your CentOS/RHEL linux, you can use one of the following command:

$ rpm -qa

Or

$ yum list installed

For Ubuntu/Debian Linux

If you are using Ubuntu/Debian Linux, and you can use the dpkg command to find out a package is installed or not. type the following command to check if httpd package is installed or not:

$ dpkg -s httpd

Outputs:

devops@devops-osetc:~$ dpkg -s httpd
dpkg-query: package 'httpd' is not installed and no information is available
Use dpkg --info (= dpkg-deb --info) to examine archive files,
and dpkg --contents (= dpkg-deb --contents) to list their contents.

From the above outputs, you should know that the httpd package is not installed in your Ubuntu Linux system.

Let’s see another example to check if wget package is installed or not, type:

$ dpkg -s wget

Outputs:

devops@devops-osetc:~$ dpkg -s wget
Package: wget
Status: install ok installed
Priority: important
Section: web
Installed-Size: 880
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Architecture: amd64
Multi-Arch: foreign
Version: 1.17.1-1ubuntu1.1
Depends: libc6 (>= 2.17), libidn11 (>= 1.13), libpcre3, libssl1.0.0 (>= 1.0.1), libuuid1 (>= 2.16), zlib1g (>= 1:1.1.4)
Recommends: ca-certificates
Conflicts: wget-ssl
Conffiles:
/etc/wgetrc c43064699caf6109f4b3da0405c06ebb
Description: retrieves files from the web
Wget is a network utility to retrieve files from the web
using HTTP(S) and FTP, the two most widely used internet
protocols. It works non-interactively, so it will work in
the background, after having logged off. The program supports
recursive retrieval of web-authoring pages as well as FTP
sites -- you can use Wget to make mirrors of archives and
home pages or to travel the web like a WWW robot.
.
Wget works particularly well with slow or unstable connections
by continuing to retrieve a document until the document is fully
downloaded. Re-getting files from where it left off works on
servers (both HTTP and FTP) that support it. Both HTTP and FTP
retrievals can be time stamped, so Wget can see if the remote
file has changed since the last retrieval and automatically
retrieve the new version if it has.
.
Wget supports proxy servers; this can lighten the network load,
speed up retrieval, and provide access behind firewalls.
Homepage: https://www.gnu.org/software/wget/
Original-Maintainer: Noël Köthe <noel@debian.org>

You can also use the dpkg-query command to achieve the same result of checking the package is installed or not, type:

$ dpkg-query -l 'wget'
$ dpkg-query -l 'httpd'

Outputs:

devops@devops-osetc:~$ dpkg-query -l 'wget'
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 wget 1.17.1-1ubuntu1.1 amd64 retrieves files from the web

devops@devops-osetc:~$ dpkg-query -l 'httpd'
dpkg-query: no packages found matching httpd

List All Installed Packages in Ubuntu

If you want to list all installed packages in Ubuntu Linux, you can use one of the following command:

$ dpkg -l

Or

$ dpkg-query -l