Bash script to control the fan of an NVIDIA GPU.

nvfanctl.sh

#!/bin/bash
# Requirements:
# Coolbits bit 2 to enable fan control.

# Dependencies:
# GNU BC: https://www.gnu.org/software/bc/

sleep_time="5s"

# On close, set fan speed back to automatic mode.
trap 'nvidia-settings -a "GPUFanControlState=0"; exit 0;' SIGINT SIGTERM
# Set fan speed to manual mode.
nvidia-settings -a "GPUFanControlState=1" 1> /dev/null

# Set the fan speed based on GPU temp, in celsius, as the argument.
set_fan_speed() {
    case "${1}" in
        [0-8][0-9])  # 0-89
            fan_speed=$(printf %.0f $(echo "1.62 + e(0.0515*$1)" | bc -l))
            ;;
        *)  # Default
            fan_speed="100"
            ;;
    esac

    nvidia-settings -a "GPUTargetFanSpeed=${fan_speed}" 2>&1 >/dev/null
    echo "Setting Nvidia fan speed: $fan_speed Temp: $1"
}


while true
do
    gputemp=$(nvidia-settings -q GPUCoreTemp | awk -F ":" 'NR==2{print $3}' | sed 's/[^0-9]*//g')

    if [ "$gputemp" != "$oldtemp" ] ; then
        set_fan_speed "$gputemp"
    fi

    oldtemp=$gputemp
    sleep "$sleep_time"
done