Linux - networking without a UI using nmcli

The XMonad setup I described in this blog post should be functional and extendable enough to get started. However there is one glaring omission - no easy way to configure any wifi or 3G/4G networks you want to connect to. So it's useful to know a little about nmcli, the command-line interface to NetworkManager. This can also be useful if you're futzing around with a linux box remotely.

Fire up an xterm and run the following to check out which network interfaces you have available, and what state they are in:

    $ nmcli dev status
    DEVICE             TYPE      STATE            CONNECTION  
    cdc-wdm0           gsm       disconnected     -- 
    wlan0              wifi      disconnected     --
    F4:31:C3:30:E3:6F  bt        disconnected     --          
    eth0               ethernet  unavailable      --          
    lo                 loopback  unmanaged        --          

So we've five interfaces, none of which are connected to anything. I'll focus on the extremely common use-cases - connecting to open and secured wifi networks using the "wlan0" device, as well as connecting to 3G/4G networks using the "cdc/wdm0" device.


To view available networks near you:

    $ nmcli dev wifi list
    *  SSID       MODE   CHAN  RATE       SIGNAL  BARS  SECURITY         
       Rotor bar  Infra  8     54 Mbit/s  72      ▂▄▆_                   
       ahnet      Infra  11    54 Mbit/s  42      ▂▄__  WEP              
       eduroam    Infra  1     54 Mbit/s  15      ▂___  WPA1 WPA2 802.1X 
       vakan      Infra  13    54 Mbit/s  12      ▂___  WEP              
       JAMU       Infra  1     54 Mbit/s  10      ▂___                   

If we want to connect to "Rotor bar" - an open, unsecured network, we can do the following

    $ nmcli device wifi connect "Rotor bar"
    Device 'wlan0' successfully activated with 'ccb0a5a1-ef8d-4fea-966f-7999f2611345'.

If this network was instead secured with the password "123456789" we would instead have used:

    $ nmcli dev wifi con "Rotor bar" password "123456789"

And when we want to disconnect from the WiFi, we can run:

    $ nmcli dev disconnect iface wlan0

And if we wanted to reconnect to this network:

    $ nmcli con up id "Rotor bar"

Mobile Broadband

We can check if you have already set up a Mobile Broadband (3G, LTE, etc seem to be appear as type "gsm") connection :
    $ nmcli connection show | grep gsm
    Vodafone CZ             2756323d-e364-49dc-9d86-92b8c2a44d15  gsm              --     

In my case I'd previously setup "Vodafone CZ" using the NetworkManager applet in XFCE, however if we want to do this in the CLI all we need to do is make sure a config file is present in the /etc/NetworkManager/system-connections folder which has the right setup

    $ sudo cat /etc/NetworkManager/system-connections/Vodafone\ CZ
    id=Vodafone CZ




So, assuming you're using Vodafone in the Czech Republic you can use this config, tweak the PIN as necessary (it's the SIM PIN, btw) rerun nmcli connection show to check NetworkManager knows about it, and then run the following to bring it up:

    $ nmcli connection up id "Vodafone CZ"
    Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/27)
And to disconnect
    $ nmcli connection down id "Vodafone CZ"
    Connection 'Vodafone CZ' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/27)

So there we have it - it's possible there's a strange configuration that you need, so you may have to dig into the nmcli man pages - but as long as you have some sort of internet connection I found the followingpages useful: