There are quite a few ways in which the code you showed can be improved.

• You should use lexical filehandles, or rather in this case directory handles.
• As documented in readdir, you need to prefix the directory name to the filenames returned, for example with catfile from File::Spec.
• readdir will return every entry in the directory, including other directories, which you can filter with -X, and including the special entires . and .., which you can filter e.g. with no_upwards from File::Spec.
• You should check the return value of move for errors.
• I don't quite understand why you want to rename all the files to single letters, but consider this: what happens if readdir happens to return the filenames in a random order, or more filenames than you have letters for? This is why below I use sort and Perl's magic string increment.

#!/usr/bin/env perl
use warnings;
use strict;
use File::Copy qw/move/;
use File::Spec::Functions qw/no_upwards catfile/;

my $dir = "/home/porter/blue";

opendir my $dh, $dir or die "$dir: $!";
my @files = grep {-f} map {catfile $dir, $_}
    sort +no_upwards readdir $dh;
closedir $dh;

my $newname = "a";
for my $file (@files) {
    my $newfile = catfile($dir,$newname);
    print "$file -> $newfile\n"; # Debug
    move $file, $newfile or warn "$file: $!";
    $newname++;
}
[download]

Update: Fixed: "sort no_upwards" was not correct, but the -f test was hiding the issue.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.