Como verificar qual navegador padrão no Linux

karthick@Ubuntu-desktop:~$ sudo update-alternatives --config x-www-browser 
There are 3 choices for the alternative x-www-browser (providing /usr/bin/x-www-browser).

  Selection    Path                    Priority   Status
------------------------------------------------------------
  0            /usr/bin/google-chrome   200       auto mode
* 1            /usr/bin/firefox         40        manual mode
  2            /usr/bin/google-chrome   200       manual mode
  3            /usr/bin/opera           90        manual mode
Mushy Macaw