Working With Files

Early Fortran systems did not use named files, but did provide a command line mechanism to equate actual file names with internal unit numbers. This facility can be emulated in a number of ways, including standard UNIX redirection.

Example: Redirecting stdin to redir.data (using csh(1)):

demo% cat redir.data 
         The data file
 9 9.9 

demo% cat redir.f 
           The source file
      read(*,*) i, z          The program reads standard input
      print *, i, z 
      stop 
      end 

demo% f77 -silent -o redir redir.f  The compilation step
demo% redir < redir.data
            Run with redirection reads data file
  9 9.90000
demo%