#!/usr/bin/perl
use strict;
use warnings;

# globbing operator will return the next matching file in local dir 
# and then false when their are no more
while (<*.txt>)
{
  print "1. Found text file: $_\n";
}

# this syntax is preferred when using variables in the pattern
my $pattern = "*.txt";
while( glob($pattern) )
{
  print "2. Found text file: $_\n";
}