How to Connect Wifi card using Command line

To scan wireless networks

sudo iwlist scanning

then change the mode to "managed"

iwconfig wlan0 mode Managed

then to set SSID

iwconfig wlan0 essid your_essid_in_double_quotes

For WEP encryption:

iwconfig wlan0 key wep_kep

And finally,tell the card to request an IP address from the router:

$ sudo dhclient wlan0

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