Debian, WiFi connection

Step-01: Make sure your USB wifi be supported on kernel list. ==>
# lsusb

Setup-02: Wlan0 IP configuration. ==>
# vim /etc/network/interfaces

Step-03: Didn't get WiFi AP connection with. ==>
# iwconfig

Step-04: WiFi, WPA2 connection. ==>
# vim /etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
     ssid="2doors"
     psk="aaaaaaaaaa"
     proto=RSN (WPA2:RSN, WPA1:WPA)
     key_mgmt=WPA-PSK
     pairwise=TKIP (AES:CCMP, TKIP:TKIP)
     auth_alg=OPEN
}
Step-05: Erase previous wpa_supplicant.conf settings. ==>
# kill -9 $(ps -ef | grep wpa | awk '{print $2}')

Step-06: Reload wpa_supplicant.conf through. ==>
# wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf
ANNEX:
1- AP scanner: # iwlist wlan0 scan
2- wpa_supplicant options:
-B: Background running
-i: WiFi interface name
-c: config file path
3- Make sure Wifi connection properly