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PROGRAM show;
 
{ SHOW.PAS displays a file, a screen at a time, using direct I/O as
  defined in the Crt unit. It demonstrates the routines:
 
      ClrScr    Eof    LastMode    ReadKey    UpCase    Write    Writeln
 
  In addition, it uses the following routines for normal text file
  operations:
 
      Assign    Close    Readln    Reset
}
 
USES
    Crt;    { by default, I/O to screen will bypass DOS }
 
CONST
    program_name = 'SHOW ';
    program_desc = ' displays the file named on the command line.';
 
VAR
    show_file : Text;
    a_line    : STRING;
    i         : Integer;
    n_lines   : Integer;
    answer    : Char;
 
BEGIN
 
    Writeln( program_name, program_desc );
    Writeln;
 
    IF ParamCount <> 1 THEN
        BEGIN
        Writeln( 'SYNTAX: show <filename>' );
        Exit;
        END;
 
     Assign( show_file, ParamStr( 1 ) );
     Reset( show_file );
 
    { Test video mode and use maximum lines for this mode. }
    IF ((LastMode AND Font8x8) > 0) THEN
        n_lines := 42
    ELSE
        n_lines := 24;
 
    REPEAT
        ClrScr;
        FOR i := 1 TO n_lines DO
            BEGIN
            Readln( show_file, a_line );
            Writeln( a_line );
            END;
        Write( 'Press ENTER for more or ''q'' to quit>' );
        answer := ReadKey;
        Writeln( answer );
    UNTIL (Eof( show_file ) OR (UpCase( answer ) = 'Q'));
 
    Writeln;
    Close( show_file );
 
END.