Dell R720 quiet fan control

dell-r720-fan-control.sh

#!/bin/bash

IDRAC_IP="192.168.0.101"
IDRAC_USER="root"
IDRAC_PASS=$1
if [ -z $IDRAC_PASS ]; then
    IDRAC_PASS=$IDRAC_PASSWORD
fi

FANS_1="0x0A" # 10%
FANS_2="0x0F" # 15%
FANS_3="0x14" # 20%
FANS_4="0x19" # 25%
# FANS_5="0x23" # 35%

restore_dynamic_control() {
    echo "Restoring dynamic fan control"
    ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASS raw 0x30 0x30 0x01 0x01
}
set_speed() {
    if [ -z $1 ]; then
        echo "No speed set"
        exit 2
    fi
    echo "Set speed: $1"
    ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASS raw 0x30 0x30 0x02 0xff $1
}
on_error() {
    restore_dynamic_control
}
trap "on_error" ERR

TEMP=$(ipmitool -I lanplus -H $IDRAC_IP -U $IDRAC_USER -P $IDRAC_PASS sdr type temperature | egrep "^Temp" | cut -d"|" -f5 | cut -d" " -f2 | sort -n -r | head -1)
echo "Highest Temp: $TEMP C"

case $TEMP in
[0-9])
    set_speed $FANS_1
    ;;
[1-2][0-9])
    set_speed $FANS_1
    ;;
3[0-9])
    set_speed $FANS_1
    ;;
4[0-5])
    set_speed $FANS_2
    ;;
4[6-9])
    set_speed $FANS_3
    ;;
5[0-4])
    set_speed $FANS_4
    ;;
*)
    restore_dynamic_control
    ;;
esac