You have just set up a new wireless network at your house, and you want to determine whether your Linux laptop has connected to it and obtained a valid IP address. What command will give you the information you need

ifconfig - a

Explanation:

ifconfig is used to configure the system's kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary. After that, it is usually only needed when debugging, or when system tuning is needed. If no arguments are given, ifconfig displays the status of the system's active interfaces.

-a display all interfaces which are currently available, even if down. source manpages: ifconfig.