#! /usr/bin/perl -w

#   scr07A.pl
#   How to access and open an external text file "Ref.txt"?                  
#   In PERL, there is no (void)main(void){ }.  Just script from top to bottom.                    
#   In PERL, instead of C's Pointer (fp), FileHandle (IN) is used.                                 
#                                
#   $_ :   This is called the default variable, that means in the context  
#          it is obvious.   In the following sample, $_ = <IN>, 
#          it is the incoming each line.
#

open (IN, "Ref.txt");

while( <IN> )       ## Get One-line each time from an external file "Ref.txt".
{   
   print $_;      ## Print out incoming each line one-by-one.  
}

close (IN);       ## Once finished the job, close the FileHandle (IN).