How can I find the newest .pl file in a directory and all its subdirectories using Perl?

Question

How can I scan an entire directory\'s contents, including its subdirectories\' contents, and find the newest .pl file within them using Perl?

I want to

Answer 1

With File::Find::Rule, and Schwartzian transform, you can get the newest file with .pl extension, in a subtree starting from dir_path.

#!/usr/bin/env perl

use v5.12;
use strict;
use File::Find::Rule;

my @files = File::Find::Rule->file()->name( '*.pl' )->in( 'dir_path' );

# Note that (stat $_ )[ 9 ] yields last modified timestamp
@files = 
   map { $_->[ 0 ] }
   sort { $b->[ 1 ] <=> $a->[ 1 ] }
   map { [ $_, ( stat $_ )[ 9 ] ] } @files;

# Here is the newest file in path dir_path
say $files[ 0 ];

The map-sort-map chain is a typical idiom: getting timestamp is slow, so we do it only one time per file, keeping every timestamp with its file in an arrayref. Then we sort the new list using timestamp ( comparing the second element of each arrayref ), and finally we discard timestamps, keeping only filenames.