music-rename.pl

#!/usr/bin/perl

#
# Author: Jason Poon
#
# Renames all files in the current directory to follow a similar format
# where the renamed filename will be of the form "$artist - [song title].$extension"
# By default the script will run in debug mode, outputting the new filename. 
#

sub println {
    local $\ = "\n";
    print @_;
}

sub usage {
    println "Usage: ./rename.pl";
    println "\t -artist [Artist Name]";
    println "\t -index [Index Value]";
    println "\t [options]";
    println "Options:";
    println "\t -ext \t File Extension";
    println "\t -r \t Run Mode";             
}

sub cap_word {
    my($string) = @_;
    my @exception = ('A', 'The', 'If', 'Is', 'It', 'Of', 'Our', 'An',
                         'On', 'In', 'But', 'With', 'Has', 'Had', 'Have');
    $string =~ s/([\w']+)/\u\L$1/g;
    foreach(@exception){
        $string =~ s/\b$_\b/lc($_)/ge;
    }

    # Capitalize the first letter
    $string =~ s/(.)/\u$1/;
    return $string;
}

my ($artistName, $titleIndex, $run);
my $separator = " - ";
my $extension = "mp3";

# Parse cmd arguments
use Getopt::Long;
$result = GetOptions("artist=s" => \$artistName,
                     "ext=s" => \$extension,
                     "index=i" => \$titleIndex,
                     "r" => \$run);

if (!$result or !$artistName or !$titleIndex) {
    die usage();
}

$extension = '.' . $extension;
@files = <*>;
chomp @files;
foreach $filename (@files) {
    if ( $filename =~ /$extension/ )
    {
        my $len_filename = length $filename;
        my $len_extension = length $extension;

        my $title = substr($filename, $titleIndex, $len_filename - $len_extension - $titleIndex);
        
        # search/replace _ with 0x20
        $title =~ s/_/ /g;
        $title = &cap_word($title);
        
        my $newName = $artistName . $separator . $title . $extension;
       
        println "Old:\t" . $filename;
        println "New:\t" . $newName;
        println "--------------------------";

        if ($run) {
            rename($filename, $newName);
        }
    }
}

exit;