$ cd /var/tmp
$ mkdir mydir
$ mkdir datadir
$ mkdir otherdir
$ touch mydir/in_mydir
$ touch datadir/in_datadir
$ touch otherdir/in_otherdir
$ cd otherdir
$ ln -s ../mydir symdir
$ ls /var/tmp/otherdir/symdir/../datadir
in_datadir
$ perl -le'opendir $dh, $ARGV[0] or die; print for grep /in/, readdir $dh' /var/tmp/otherdir/symdir/../datadir
in_datadir