#!/bin/bash

STEP=30
CNT=5

for speed in full-speed 7 6 5 4 3 2 1 0
do
  echo "level $speed" > /proc/acpi/ibm/fan
  sleep 120;

  rm /tmp/fan-speed 2>/dev/null
  for i in `seq 1 $CNT`
  do
    cat /proc/acpi/ibm/fan |grep ^speed | cut -d ':' -f 2 >>/tmp/fan-speed
    sleep $STEP
  done

  EXPR=`cat /tmp/fan-speed | sed "s/$/+/" ; echo 0`
  EXPR=`echo $EXPR`
  AVG=`echo "($EXPR)/$CNT" | bc -l | sed "s/\..*$//"`;

  echo "Level=$speed; Avg. speed="`printf "%4d" $AVG`"rpm"

done