#!perl

use utf8;

my $directory = '.';
opendir (MYHANDLE , $directory) || die "Cant open directory :$!\n";
my @files = readdir MYHANDLE;
closedir MYHANDLE;
foreach (@files) {
  my $original = $_;
  s/canción/poesía/;
  rename "$directory\\$original", "$directory\\$_";
}

##</code><code>##

canción de la vida.txt
canción de la naturaleza.txt
canción &#21644;&#24179;&#20043;&#27468;.txt
...