reset network manager ubuntu if-down.d code example

Example 1: linux restart all network interfaces

sudo service network-manager restart

Example 2: sudo systemctl restart networking

Linux Network
#To Restart network
$ sudo /etc/init.d/networking restart

#To stop and start use the following option (do not run them over remote ssh session as you will get disconnected):
$ sudo /etc/init.d/networking stop
$ sudo /etc/init.d/networking start

#Debian/Ubuntu Linux with systemd, run:
$ sudo systemctl restart networking
           or 
$ sudo systemctl restart NetworkManager.service