Debian Configuration :: Systemd Custom Service

On macbook air 6.2, i've installed a Debian jessie mate DE, dual boot using refind. I'm currently fine-tuning it. I've made a script following powertop advice:

Code: Select all[newb@debian /etc/systemd/system]$ cat mba_kb_sp.sh
#!/bin/sh
echo 'auto' > '/sys/bus/usb/devices/1-3.1/power/control';
echo 'auto' > '/sys/bus/usb/devices/1-3.2/power/control';
echo 'auto' > '/sys/bus/usb/devices/1-5/power/control';
exit 0

[Code] ....

All seems to work fine, however when i check the sys file it didn't change. But I can start manually the systemd service and, this time, it works.