Since this is a newbie tutorial, it may be worth explaining that the contents of the record read are available in the $_ variable, in the block "... do something here...".

For example, if you wanted to PRINT the file, you would say:

while (<$f>)
{
  print $_; # $_ contains the record most recently read

  #  The "$_" is implied if omitted, so you could simply
  #  say:    print;  
  #
  # If you need to append a newline after each record,
  #  use :  print "$_\n";
}
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