Here's a bit of example code that I often use:

use File::Find;

sub eachFile {
  my $filename = $_;
  my $fullpath = $File::Find::name;
  #remember that File::Find changes your CWD, 
  #so you can call open with just $_

  if (-e $filename) { print "$filename exists!\n"; }
}

find (\&eachFile, "mydir/");