The Advanced Packaging Tool (APT) works on both Debian / Ubuntu and it can handle the installation and removal of software. You need use apt-get command as follows to forcefully reinstall package. The syntax is:
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/
The following command will reinstall rsync package. Open a terminal and then type:
$ sudo apt-get --reinstall install rsync
# apt-get --reinstall install rsync
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