prefix -- change prefix

syntax:  prefix <pathname>

ex:      prefix /disk/dir
         prefix x/y
         prefix %help
         prefix .62blah
         prefix m=
         /mydisk/dir1
         .61

Changes the prefix (which is displayed as your prompt in 
Davex).  (Typing 'prefix' with no pathname makes your prefix 
empty; this is not usually desirable.)

Note that an IMPLIED prefix command is done if you type a
complete pathname (including one starting with "%" or ".xx"),
or if a partial pathname is found in your scan list.

If a partial pathname is given, it is appended to the 
current prefix.  So "prefix letters" when your prefix is 
already "/disk" will make your prefix "/disk/letters".

You can also set your prefix just by typing the name of a 
directory.  The process is not quite the same--if you type a 
partial pathname, Davex uses your scan list to find the 
directory.  It follows the same rules as for launching SYS 
or S16 files, but if it finds a DIR, it just sets your 
prefix.

For example, if the first entry in your scan list is "*", 
you can always change to a subdirectory of the current 
directory just by typing the subdirectory's name (unless 
that name is an internal Davex command!).

(see also:  origin, up, top, over, scan)