I have a raspberry pi 2 and installed the Raspbian Version from 2015-05-05. As "boot option" I chose "Console Text console..." because I don't want a full desktop. I logged in from my remote PC via SSH (putty). I want to start Firefox but get the following error: root@raspberry:~# firefox (process:2425): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size = = 0' failed Error: no display specified If I try to start xclock I also get an error: root@raspberry:~# xclock Error: Can't open display: I want to start the programs on my display connected via HDMI. Even if I do this directly on my raspberry console it doesn't work. How can I tell my raspberry to display this programs on my via HDMI connected Display?