sambaの設定

https://qiita.com/neomi/items/645e2c7184210f989828

シェルスクリプト経由で低電力を知る

https://qastack.jp/raspberrypi/60593/how-raspbian-detects-under-voltage

https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=147781&start=50#p972790

/opt/vc/bin/vcgencmd get_throttled
->
throttled=0x0

ビットの意味

0: under-voltage
1: arm frequency capped
2: currently throttled 
16: under-voltage has occurred
17: arm frequency capped has occurred
18: throttling has occurred

http://www.neko.ne.jp/~freewing/raspberry_pi/raspberry_pi_3_about_low_voltage_warning/