defrag [/C] [drive:] [{/F|/U}] [/Sorder[-]] [/B] [/X] [/A] [/FO]
drive:
This is the drive letter of the drive you wish to defragment. For instance:
defrag c:
/C
Defrag will not use its menu-driven user interface if you use this option. It
will communicate through the command line instead.
You must use the [drive:] option, as described above, when you use
the /C switch.
/F
With this option, defrag will perform a full optimisation by making sure
that all files are at the beginning of the disk, with no gaps in between.
/U
With this option, defrag will unfragment the files, but gaps may be left
between files.
/Sorder[-]
Defrag will sort files into the given order:
N by Name (alphabetic) E by Extension (alphabetic)
D by Date & time (earliest first) S by Size (smallest first)
Postfix the order with a hyphen - to sort descending.
/B
Reboots the computer after defrag completes the optimisation.
/X
Forces defrag to exit as soon as it completes the optimisation.
/A
With this option, defrag will give an audible warning before taking action.
/FO:
For use with the /C option, this tells defrag to give a more full
output of information.
Fragmentation is a normal process on DOS disks.