Explain relationship between file storage size and EOF.

usr.bin/du/du.1

@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd April 15, 2026
+.Dd July 16, 2025
 .Dt DU 1
 .Os
 .Sh NAME
@@ -51,6 +51,14 @@ argument.
 If no file is specified, the block usage of the hierarchy rooted in
 the current directory is displayed.
 .Pp
+Normally block usage closely resembles the file size, but this is
+not always the case.
+For files with an incomplete last block, the size will be larger.
+The size includes any metadata such as indirect blocks, though not the
+inode.
+For sparse files or file systems that defer writing data to disk the
+count will be less than the file size.
+.Pp
 The options are as follows:
 .Bl -tag -width indent
 .It Fl -libxo
@@ -225,8 +233,8 @@ Also display a grand total at the end:
 .Xr chflags 2 ,
 .Xr fts 3 ,
 .Xr libxo 3 ,
-.Xr symlink 7 ,
 .Xr xo_options 7 ,
+.Xr symlink 7 ,
 .Xr quot 8
 .Sh STANDARDS
 The