ken@titan ~/tmp/www
$ perl -Mstrict -Mwarnings -Mautodie=:all -MCarp::Always -T -E '
    use FindBin qw{$RealBin};
    my $safepath;
    BEGIN {
        if ($RealBin =~ m!^(/home/.+?/(tmp|xyz)/www)!) {
            $safepath = "$1/../lib";
        }
        else {
            die "Insecure access!";
        }
    }
    use lib "$safepath";
    use PDF::API2;
    my $pdf = PDF::API2->new("some.pdf");
    $pdf->save("some.pdf");
'

##</code><code>##

    my $pdf = PDF::API2->open("some.pdf");

##</code><code>##

ken@titan ~/tmp/www
$ file some.pdf
some.pdf: PDF document, version 1.4, 0 pages

##</code><code>##

delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};   # Make %ENV safer