i ran the command
i also deleted the offending line
wifi connection is showing in network manager but it is not connecting
i also ran
wlan0 IEEE 802.11bgn ESSID:"RFNet"
Mode:Managed Frequency:2.462 GHz Access Point: 9C:D6:43:16:21:20
Bit Rate=2 Mb/s Tx-Power=16 dBm
Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality=48/70 Signal level=-62 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:1457 Missed beacon:0
lo no wireless extensions.
eth0 no wireless extensions. when i connect with mobile broadband or modem it gives the ip address of wifi network and if i want to istall or update anything via teminal it just do this % [Connecting to 192.168.100.3 (192.168.100.3)] [Connecting to 192.168.100.3 but it dow not connect...help me....i am new to ubuntu