apt-get --reinstall install PackageNameHere

OR

apt-get --reinstall install Package1 Package2

The --reinstall option re-install packages that are already installed and at the newest version.

Pro tip: Backup configuration files before you reinstall packages. For example, if you are reinstalling nginx web server package, backup /etc/nginx/ with cp command i.e. mkdir /root/nginx.mmddyyyy/; cp -avr /etc/nginx/* /root/nginx.mmddyyy/

Examples

The following command will reinstall rsync package. Open a terminal and then type:
$ sudo apt-get --reinstall install rsync
OR
# apt-get --reinstall install rsync
Sample outputs:

If above method failed for you, try the following syntax. Make sure you backup config file before typing the following commands. Please note that the --purge option is identical to remove except that packages are removed and purged including any configuration files are deleted too.

sudo apt-get --purge remove package1
sudo apt-get install package1

See also

• See man pages for more info – apt-get(8),dpkg(1),cp(1)