Stephen Harris wrote: > And, remember, that the output of "df" might have changed in between > times you ran "df" and you ran the "awk" command; there's only 7Mbytes > difference. Did someone delete a 7Mbyte file? Send email? Finish a > print job? Or... could be plenty of reasons for the used amount to > go down. > > The awk script works correctly, as can be tested easily: > > $ cat h > Filesystem 1024-blocks Used Available Capacity Mounted on > /dev/mapper/VolGroup00-LogVol00 274405432 18584656 241656808 8% / > /dev/sda2 101105 19096 76788 20% /boot > tmpfs 1682508 0 1682508 0% /dev/shm > > $ cat h | awk '/^\/dev\// { avail += $3/1024 } END { printf("%d Mb used\n",avail)}' > 18167 Mb used > > But the whole system used only 18 MB ? That's not true.