#!/usr/bin/perl

$fname = "empty";

while ($fname ne '/Users/johnsmith/data/$fname*'){
       print "Please enter Filename: ";
       chomp($fname = <STDIN>);

if ($fname ne '/Users/johnsmith/data/$fname*'){
   print "File does not exist.\n\n";
   print "Please enter Filename: ";
}
}
print "I have found this $fname in your directory\n\n";