Copying files that starts with numbers to another directory - perl

Question

I've solved #1, But I got 2 question left.
Anyone that can help me?
From the directory local dir, list all the files that start with a number (0..9) and which file
extension is .song
Create the subdirectory ”local dir/selected” in which you will copy each one of these files after
numbering each (non blank) line in each one of them.
Print out, in a file called stats.txt, the following informations concerning each one of the files:
a) Number of (non blank) lines.
b) Number of paragraphs. A paragraph here is a block of text composed of non empty lines and
delimited at its beginning and at its end by either the beginning of the file, the end of the file or
by a blank line.
c) The mean size of a paragraph (in number of lines).
d) If, yes or no, all paragraphs in the file have the same length.
Bonus questions:
e) Detect each rhymes present in each file.
f) Give the ratio of rhyming lines towards the total number of lines.
For #1:
#!/usr/bin/perl
use strict;
use warnings;
my $directory = '/local_dir';
opendir (DIR, $directory) or die $!;
while (my $file = readdir(DIR))
{
# Use a regular expression to find files ending in .song.txt
next unless ($file =~ m/\.song.txt$/);
print "$file\n";
}
closedir(DIR);
exit 0;

Answer 1

Here's how you might go about doing the first and second step:
#!/usr/bin/env perl
use strict;
use warnings;
use autodie;
my $src_dir = '';
my #files = glob $src_dir . qq([0-9]*.song.txt);
my $dest_dir = 'selected';
mkdir $dest_dir;
for my $file (#files) {
open my $fin, "<", $file;
open my $fout, ">", "$dest_dir/$file";
my $c = 1;
while (<$fin>) {
$_ = $c++ . " $_" unless /^$/;
print $fout $_;
}
}
Rather than using opendir, you can use glob to find the files that you are interested in, starting with a number [0-9] and ending with .song.txt. After creating the output directory, the for loop goes through these files and creates a new file in the destination directory with the same name. The while loop goes through each line of the input file. It adds a number to the start of each line if it is not blank, i.e. the start of the line is not followed immediately by the end of the line /^$/. Then it writes the line to the new file.
As for the third step, I think that it would be worth you having a go at that yourself and asking a new question if you get stuck.