[CentOS] df to get total disk usage on all filesystems?

[Stephen Harris]

On Thu, Aug 14, 2008 at 01:12:58AM -0700, MHR wrote:
> On Wed, Aug 13, 2008 at 8:56 PM, Lunix1618 <lunix1618 at gmail.com> wrote:
> > [root at centos-svr ~]# df -kPl
> > 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
> >
> > and with the command of Stephen :
> > [root at centos-svr ~]# df -Pkl | awk '/^\/dev\// { avail += $3/1024 } END { printf("%d Mb used\n",avail)} '
> > 18173 Mb used

> Well, I get 18167, but that's not too far off.

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

-- 

rgds
Stephen