After upgrading to Maverick Meerkat yesterday, my Guake terminal started giving the following error on executing top:
TERM environment variable not set.
You can fix the error by doing exactly what error says – set the TERM variable. To do that execute the following in terminal:
echo -e "TERM=xterm\nexport TERM" >> ~/.bashrc
Kill the guake terminal
kill -9 $$
You don’t need to run guake again, just press your keyboard shortcut to bring back Guake and it will appear. Now you can execute commands as normal.