1. To find out the interfaces on your system, type: ifconfig -a
2. Lets assume your interface name is "pcn0"
3. Run "ifconfig pcn0 plumb"
4. Run "ifconfig pcn0 dhcp start" to bring the interface up and get a DHCP address (assuming you have a DHCP server for the subnet your host is on)
5. Create empty files named /etc/hostname.pcn0 and /etc/dhcp.pcn0
6. Reboot: shutdown -i6 -g0 -y

Ubuntu Linux Software update using command line tools
apt-get is the command-line tool for handling packages, updating package and installing patches under Ubuntu Linux. All you have to do is type the following two command to update all installed software to latest version.
Open terminal and type the following two commands: $ sudo apt-get update $ sudo apt-get upgrade Sample output: