#!/usr/bin/perl
use strict;
use warnings;

my @dirs = qw (
C:\somedirectory\anotherDirectory\WorkingDirectory\myFile.txt
C:\somedirectory\anotherDirectory\WorkingDirectory\Logs\myLogs.txt
C:\somedirectory\anotherDirectory\WorkingDirectory\Stuff\myStuff.txt
C:\someBSdirectory\bogus.txt
);

foreach my $dir (@dirs)
{
    print "$1\n" if $dir =~ /(\\WorkingDirectory.*$)/;
}

__END__
prints:
\WorkingDirectory\myFile.txt
\WorkingDirectory\Logs\myLogs.txt
\WorkingDirectory\Stuff\myStuff.txt
[download]

Update: After seeing some other replies, I would advise to use the "/" character instead of the "\" character in delimiting program paths. In Perl using "/" instead of "\" works just fine on both Unix and Windows and I recommend it.