CentOS / RHEL: yum Command Reinstall Package

I accidental deleted the configuration file stored in /etc/ directory and the latest backup were made yesterday. How do I resinstall the package using the yum command under RHEL / CentOS Linux server?

You can use the yum command with reinstall option. This will reinstall the identically versioned package as is currently installed. The syntax is as follows:

 
yum reinstall packageName
yum reinstall packageName1 packageName2
 

In this example reinstall a package called keepalived, type:
# yum reinstall keepalived
Sample outputs:

Loaded plugins: product-id, rhnplugin, subscription-manager
Updating certificate-based repositories.
Setting up Reinstall Process
Resolving Dependencies
--> Running transaction check
---> Package keepalived.x86_64 0:1.2.2-2.el6 will be reinstalled
--> Finished Dependency Resolution
Dependencies Resolved
=================================================================================================================================================
 Package                             Arch                            Version                                 Repository                     Size
=================================================================================================================================================
Reinstalling:
 keepalived                          x86_64                          1.2.2-2.el6                             epel                          147 k
Transaction Summary
=================================================================================================================================================
Reinstall     1 Package(s)
Total download size: 147 k
Installed size: 380 k
Is this ok [y/N]: y
Downloading Packages:
keepalived-1.2.2-2.el6.x86_64.rpm                                                                                         | 147 kB     00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : keepalived-1.2.2-2.el6.x86_64                                                                                                 1/1
Installed products updated.
Installed:
  keepalived.x86_64 0:1.2.2-2.el6

Note: This does not work for "installonly" packages such as RHEL kernels packages.