get_fan_tmp.sh error

[boebo]

when i start the script get_fan_tmp.sh i get the message:

/home/pi/get_fan_tmp.sh: line 5: -2: substring expression < 0

Unfortunately, I can't do anything with the message. Can you help me?

[spawnrider]

Hello,

Could you try to read the temperature value return by the raw script below ?

#!/bin/bash
read TEMP < /dev/ttyUSB0
echo ${TEMP}

[boebo]

now i get an empty output.