Program Input and Output

Reading from the Diamond Operator

• The diamond operator <>, works just like the <STDIN> operator, except it gets it inputs from a different source then the Standard Input pipe.
• Instead, <> reads successively through each line of all files specified on the command line that invoked the Perl program.
• The <> operator does not return undef until all lines from all specified files have been read.
• Example:
  

  # Another Cat.  Dump the contents of all files specified on command line
  while ( <> ) {
      $userInput = $_;
      print $userInput;
  }
  

• Note that in actuality, the <> operator works on the @ARGV array, which by default contains the command line arguments. If you wish, you may replace this array with your own values and continue to use the <> operator.