FreeBSD PfSense IPMI Manual Fan Control

#!/bin/csh
# cfan.sh
# Manaual control over fans in PfSense (FreeBSD) on a Dell PowerEdge R210 ii system
# Original script: https://www.garron.me/en/bits/specify-editor-crontab-file.html
# Install:
# sudo pkg install ipmitool
# Add ipmi_load="YES" to /boot/loader.conf
# Add this script to /usr/bin/
# Add * * * * * /bin/csh /usr/bin/cfan.sh to cron file with sudo crontab -e
# Reboot

set temp_min=20
set temp_max=70

set fan_min=20
set fan_max=100

# Percentage of the old reading which will be used to calculate the new fan speed
set force=75

# Seconds between each reading
set delay=3

# Average only when difference is less than
set avg_skip=10

echo "Fan control started"

set fan_speed_old=58

if ( -f "/tmp/last_speed" ) then
    set fan_speed_old=$(sed -n '1p' < "/tmp/last_speed")
    echo "Last speed was $fan_speed_old"
endif

# Enable manual control
ipmitool raw 0x30 0x30 0x01 0x00 > & /dev/null

while (1)
# Edit to work on BSD systems
    set CURRENT_TEMP=`sysctl dev.cpu | grep temperature | awk '{print $2}'`
    set AVERAGE_TEMP=0
    set NUMBER_OF_CORES=0
    #Take the average temperature reading of all cores
    foreach core_temp ($CURRENT_TEMP)
        # Remove "C" from the end of the readings
        set core_temp=`echo "$core_temp" | sed 's/.$//'`
        set AVERAGE_TEMP=`echo "$AVERAGE_TEMP + $core_temp" | bc -l`
        set NUMBER_OF_CORES=`echo "$NUMBER_OF_CORES + 1" | bc -l`
    end
    set temp=`echo "scale=0; $AVERAGE_TEMP / $NUMBER_OF_CORES" | bc -l`
# End edit

    echo "CPU Temp: $temp"

    @ fan_speed=($temp - $temp_min) * ($fan_max - $fan_min) / ($temp_max - $temp_min) + $fan_min

    set res=`echo "$fan_speed-$fan_speed_old" | bc`

    if ( $res < 0 ) then
        set res=`expr 0 - $res`
    endif

    if ( $res < $avg_skip ) then
        echo " Averaging:"
        set cforce=$(echo "scale=2;$force/100" | bc)
        set old=$(echo "scale=2;$fan_speed_old*$cforce" | bc -l)
        echo -e "  Old speed $old"

        set cforce=$(echo "scale=2;1-$cforce" | bc)
        set new=$(echo "scale=2;$fan_speed*$cforce" | bc -l)
        echo -e "  New speed $new"

        set fan_speed=$(echo "scale=0;$old+$new" | bc)
        set fan_speed=$(echo "($fan_speed+0.5)/1" | bc )
        echo -e "  Fan speed: $fan_speed"
    endif

    set fan_speed_old=$fan_speed

    if ( $fan_speed < $fan_min ) then
        set fan_speed=$fan_min
    else if ( $fan_speed > $fan_max ) then
        set fan_speed=$fan_max
    endif

    set cmd="0x30 0x30 0x02 0xff 0x$fan_speed"
    echo "Command: $cmd"

    # Set fan speed
    ipmitool raw $cmd > & /dev/null

    set current=$(date +"%S")
    set current=$(echo $current | sed 's/^0*//')
    if ( $current > 51 ) then
        echo $fan_speed_old > /tmp/last_speed
        sleep 1
        exit
    endif

    echo -e ""

    sleep $delay

    break
end