Viewers...
 This command is used  to  create  and  maintain  the  viewer
 extension file, which associates different viewers with file
 extensions. This feature allows you to use different viewers
 to view files with different extensions.

 Lines in the VCVIEW.EXT file consists of the extensions, and
 the  commands  to  view  files  with that extension (usually
 these commands are viewers):

        +---- Extension
        |               +--- Insert file name and extension
        .               .
       dbf: dbview.exe !.!
            @ cls
            +------------+
               Commands

 tells the Commander to run Data Base viewer when  you  press
 F3 on a file that ends in .dbf (such as "somename.dbf"), and
 then to clear the screen.

 A comment line must contain symbol ' in first column.

 You can type symbol @  before  any  DOS  command  to  cancel
 output of the prompt and the command line.

 Here are all the ! arguments that you can use in commands:

   Argument     What                             Example
   --------     ---------------------------      ------------
   !.!          File name with the extension     filename.ext
   !            File name, without extension     filename
   !:           The current drive letter         A:
   !\           The current page                 \PATH
   !!           Insert the `!' character         !

   Notes:
     .  You  can  use  ":"  to  match  any  file  without  an
        extension.

     .  You can use DOS wildcard characters. So, for example,
        "*:" will match any extension.

     .  There  are  two  types of viewer extension file: Main
        and Local. The main extension file is stored  in  the
        same  directory as the  Commander (or  the  directory
        given by  the  VC  environment  variable). The  local
        extension file is an extension file  in  the  current
        directory. This  allows  you  to  have  a  number  of
        extension files in different directories.

     .  There is  an  alternative  format  to  load  standard
        viewers. The extension  file  item  must  consist  of
        the extension and the viewer's name  with  extension.
        You should not  use  symbol  @  and  the ! arguments.
        Point the drive letter and the  path  if  the  viewer
        locates  in  a  different  drive  or  directory.  For
        example
                   dbf: c:\progs\dbview.exe

     .  Press Alt+F3 to use the built-in viewer.