The following applies to Ubuntu Linux mainly. May or may not work on other distros.

Miscellaneous

List video driver
lshw -c video

Networking

When troubleshooting network problems a good thing to do is first to stop network-manager. Network-manager tries automatically to do stuff like connecting to networks so it can be complicated to figure out what’s going on

Start or stop network-manager
sudo service network-manager start/stop

Set a static IP adress
sudo ip addr add 192.168.1.2/24 broadcast 192.168.1.255 dev
or
ifconfig wlan0 10.1.7.13 netmask 255.255.255.0 up

Joining a wifi network
iwconfig wlan0 essid THE_NETWORK_NAME

check status of wifi
iw wlan0 link
or
iwconfig

start or stop the device wlan0
sudo ip link set wlan0 up/down
sudo ip link set eth0 up/down

get an IP from dhcp
dhclient eth0

start network manager front end

killall nm-applet
sudo nm-applet

Good resource for wifi signal
http://www.cyberciti.biz/tips/linux-find-out-wireless-network-speed-signal-strength.html

iwconfig wlan0

Excellent tool to check wifi signal from command line
apt-get install wavemon
wavemon

# ADHOC NETWORK
==================
# set the mode
sudo iw wlan0 set type ibss
sudo iw wlan0 ibss join
e.g : sudo iw wlan0 ibss join myadhoc_net 2427
#check with iwconfig or iw wlan0 link