disk-over-time.sh

#!/bin/bash

dt=`date +%D`
log="du.log"

df > /tmp/du$$

while read line
do
    fields=`echo $line | awk '{print NF}'`
    case $fields in
    5) echo -n "$dt " >> $log
        echo $line | awk '{print $5,$4}' >> $log;;
    6) echo -n "$dt " >> $log
        echo $line | awk '{print $6,$5}' >> $log;;
    9) echo -n "$dt " >> $log
        echo $line | awk '{print $8,$9}' >> $log;;
    10) echo -n "$dt " >> $log
        echo $line | awk '{print $9,$10}' >> $log;;
    esac
done < /tmp/du$$

rm /tmp/du$$