backup dos command

== BACKUP ==
'''External - DOS 2.0 and above'''
:Backs up one or more files from one disk to another.

<pre>
BACKUP source destination-drive: [/S] [/M] [/A] [/F[:size]]
  [/D:date[/T:time]] [/L[:[drive:][path]logfile]]

  source             Specifies the file(s), drive, or directory to back up.
  destination-drive: Specifies the drive to save backup copies onto.
  /S                 Backs up contents of subdirectories.
  /M                 Backs up only files that have changed since the last
                     backup.
  /A                 Adds backup files to an existing backup disk.
  /F:[size]          Specifies the size of the disk to be formatted.
  /D:date            Backs up only files changed on or after the specified
                     date.
  /T:time            Backs up only files changed at or after the specified
                     time.
  /L[:[drive:][path]logfile]
                     Creates a log file and entry to record the backup
                     operation.
</pre>