  \/ B - B A C K U P \/

Makes a filestore copy of the editor's workfile, but if a file would be
overwritten then it is retained by renaming it <pathname>.BU. If <pathname>.BU
exists already, the user is asked if he wants to delete it: a 'no' answer
abandons the command. See also S-SAVE for the consequences regarding protection
and ownership.

Parameter
 <pathname> optional if there has been a previous B-BACKUP, S-SAVE or Q-QUIT
	    command with a <pathname> or if Q was invoked with one originally,
	    in which case the previous parameter applies.

File position
 This command leaves the file position unaltered.
