The syntax is simple and easy to use. You can renew your DHCP address when using Linux as follows:
sudo dhclient -r sudo dhclient -vr eth0 sudo dhclient -v eth0
You can also use the following command on Ubuntu/Debian and other distro where network-manager used to control interfaces:
sudo service network-manager restart
Or use nmcli on modern Linux distro such as Ubuntu LTS:
nmcli con down id 'ConnectionNameHere' nmcli con up id 'ConnectionNameHere'
See dhclient(8) for more information.