BACKUP
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Format:        BACKUP  [source  [dest]] [/D] [/F]  [/M]  [/T] 
          [/V] [/X]

Purpose:       Backs up files and directories on a disk.

Use:           source  consists  of [d:]  [path]  [filename]. 
          dest consists of [d:] [path].

               If dest is not given,  then it defaults to the 
          current  drive.  If neither the source nor dest are 
          given,  then  BACKUP  prompts for both  drives  and 
          paths.  If  both  the source  and  the  destination 
          drives refer to the same physical drive (because an 
          ASSIGN  is  in operation),  then an error  will  be 
          given.  Operation with MAPDISK in operation however 
          will  continue  as  usual,  with  prompts  for  the 
          insertion  of the correct disk.  Thus BACKUP can be 
          used  on a singe drive system,  although many  disk 
          changes may be necessary.

               If no filename is given for the source,  or if 
          an ambiguous filename is specified which includes a 
          match  with a directory name,  then all  descendant 
          files and sub-directories of that directory will be 
          included  in the backup operation.  If  the  backup 
          operation includes the root directory of the source 
          then  the volume name will be copied along with the 
          files and directories.

               It  is  not possible to specify the  names  of 
          files  and directories created on  the  destination 
          disk;  they are always given the same names as they 
          have on the source. Following the backup operation, 
          the  destination disk will have the same  directory 
          structure  as  the source disk,  starting from  the 
          destination path specified.

               If  the /D option is given,  then  the  backup 
          operation   is  restricted  to  the  files  in  the 
          directory specified by the source path.  Descending 
          directories and their files and directories are not 
          included.

               If the /F option is given,  then all files and 
          directories   on  the  destination  disk  will   be 
          destroyed, irrespective of their attributes (hidden 
          or  read only etc.).  If the destination is  not  a 
          valid  formatted  VT-DOS compatible disk  then  the 
          entire disk will be re-formatted as one.

               The /M option is used when BACKUP is used as a 
          formal  archive  operation.   Whenever  a  file  is 
          changed   (written  to)  by  VT-DOS,   an   archive 
          attribute  is  set (similar to the hidden and  read 
          only attributes).  The /M option will cause  BACKUP 
          to only copy files with this archive attribute set, 
          and  then  to reset it.  Thus is BACKUP /M is  used 
          regularly  on  a disk then only those  files  which 
          have changed since the last backup will be copied.

               The /T option causes BACKUP to put the current 
          date  and  time on the destination  files.  If  not 
          given, then the destination files will be given the 
          date and times of the source files.

               If /V is given, then disk verification will be 
          turned on for the duration of the backup. This will 
          have no effect if verification is already set  (see 
          HELP VAR).

               The   /X  option  will  suppress  all  warning 
          prompts normally issued by BACKUP, thus aiding it's 
          use in batch files.

               The default operation of BACKUP is designed to 
          facilitate  the  creating of  backups  of  complete 
          disks, and has several advantages over DISKCOPY. It 
          will  be  quicker  if the source disk is  not  very 
          full,  it  consolidates all files  into  contiguous 
          blocks  on  the destination disk (speeding up  file 
          reads and writes),  it does not promulgate any disk 
          errors  on the source disk,  and it can be used  to 
          copy  data  from  one format disk to a  disk  of  a 
          different format (eg. from a 40 track disk to an 80 
          track disk).

               Note  that this is a  transient  command,  and 
          must be loaded from disk.

Examples:

     BACKUP

               Since  no  parameters  are  given,  this  will 
          prompt  for  the source and destination  disks  and 
          then perform the backup using the default options.


     BACKUP A: B:/X

               This  will backup drive A:  to drive B:,  with 
          warning prompts suppressed.  This may be part of  a 
          backing up batch file.


     BACKUP A:\DATA B:DATABAK/D/M

               All  files in the directory \DATA on drive A:, 
          excluding  sub-directories in that  directory,  are 
          copied to the directory \DATABAK on drive B:.  Only 
          files that have been modified since this  operation 
          was last done are copied.
