Hue-shell supplies a service file for the next generation init system of Linux. To run hueshell-default on startup enable the hue-shell.service:

systemctl enable hue-shell.service

Edit the default scene section in /etc/hue-shell/hue-shell.conf to specify the wanted scene for hueshell-default.

# Default light scene for the startup daemon.                                   
#DEFAULT_SCENE="huescene-sequence -H 4000,12750,6000,14500 -s 3 -t 1 -b 255"    
#DEFAULT_SCENE="huescene-breath -H 46000:48000 -b 1:255 -t 15:20"