1) Find out the wireless device name.
#iw dev
2) check wireless device status up or down
#ip link show wlan0
3) scan wireless networks
#iw wlan0 scan
Now to configure and connect wireless without GUI we will require package wpa_supplicant-0.7.3-9.el6.i686
4) Create a configuration file
#wpa_passphrase >> /etc/wpa_supplicant/wpa_supplicant.conf
5) To start the device through command line
#wpa_supplicant -B -D wext -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf
where -B means run wpa_supplicant in the background.
-D specifies the wireless driver. wext is the generic driver.
-c specifies the path for the configuration file.
put above command in /etc/rc.local so that after booting it will automatically connect to wireless device.