Troubleshoot Truncated icons Revert to Ubuntu Mono Nerd Font 2.0 Brightness permission denied Add these lines in /etc/udev/rules.d/95/backlight.rules: RUN+="/bin/chgrp video /sys/class/backlight/intel_backlight/brightness" RUN+="/bin/chmod g+w /sys/class/backlight/intel_backlight/brightness"