The easiest way is to use readdir together with stat and sort.

Something like this:

use 5.020;

my $dir = '\\\\server\\share\\my\\path';

opendir my $dh, $dir
    or die "Can't opendir '$dir': $!";
my @files = map { "$dir\\$_" }   # convert filenames to absolute filen
+ames with UNC path
            grep { !/^\.\.?\z/ } # ignore "." and ".."
            readdir( $dh );

my %last_modified = map { $_ => -M $_ } # cache the last modified time
                    @files;

@files = sort { $last_modified{ $a } <=> $last_modified{ $b } } @files
+;

say $files[0];
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Update: Ignore . and .. entries, spotted by Marshall

TIMTOWTDI

#!/usr/bin/perl

use strict; # https://www.perlmonks.org/?node_id=11154077
use warnings;
use List::AllUtils qw( min_by );

my $dir = '.'; # FIXME to your path

my $mostrecent = min_by { -M } <$dir/*>;

print "most recent file: $mostrecent\n";
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