How to List Installed Packages on CentOS ?

In this tutorial, we will show you how to list and filter the installed packages on CentOS. In situations where the same software package needs to be installed on another machine or the system needs to be reinstalled, it may be helpful to know how to list the installed packages on the CentOS system.

We will also show you how to check if a specific package is installed, count the installed packages and find the version of the installed package.

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List the packages installed with Yum
YUM (Yellow Dog Update Program) is the default CentOS package manager. It can be used to download, install, delete, query and manage CentOS RPM packages from official and third-party CentOS repositories.

To use yum to list the installed packages on the CentOS system, use the following command:

sudo yum list installed

It will print a list of all installed packages, including information about the version and repository of the RPM package.

Usually, the list of packages is very long. To improve readability, it is best to pipe the output to less:

sudo yum list installed | less

To determine whether a particular package is installed, use the grep command to filter the output.

For example, to determine whether the unzip package is installed on the system, you can run:

sudo yum list installed | grep unzip
unzip.x86_64 6.0-19.el7 @anaconda

The above output shows that the 6.0-19 decompressed version is installed on the computer.

List installed packages with Rpm
The rpm command with the -q option allows you to query packages.

The following command will list all installed packages:

sudo rpm -qa

To query (search) whether a certain package is installed, pass the package name to the rpm -q command. The following command will show you whether the tmux package is installed on your system:

sudo rpm -q tmux

If the package is installed, you will see something similar to the following:

tmux-1.8-4.el7.x86_64

Otherwise, the command will print:

package tmux2is not installed

To get more information about the parcel pass in question, -i:

sudo rpm -qi tmux

Create a list of all installed packages
To create a list of names of all installed packages on the CentOS system and save it in a file named packages_list.txt, redirect the command output to a file:

sudo rpm -qa> packages_list.txt

To install the same packages on other servers, you can use the cat command to pass all packages to yum:

sudo yum -y install $(cat packages_list.txt)

Count the number of installed packages
To find out how many packages are installed on the system, use the same command as before, but instead of redirecting the output to a file, pipe it to the wc utility to count the lines:

sudo rpm -qa | wc -l

603

The above output shows that 603 packages have been installed.

in conclusion
In the CentOS system, you can use the yum list installed and rpm -qa commands to list the installed packages.