i use redhat9.0 .when i use df .it show
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda8 4743776 3818208 684596 85% /usr
/dev/hda6 396623 96105 280037 26% /var
but 4743776-3818208-684596=240972(k)
396623-96105-280037=20481(k)
where is this spaces?