'/var/tmp/otherdir/symdir/../datadir' => '/var/tmp/otherdir/datadir'
'/var/tmp/mydir/../datadir' => '/var/tmp/datadir'

##</code><code>##

Finding a data path:

dirname($name):/tmp/../datadir
dirname(rel2abs($name)):/tmp/../datadir
dirname($0):/usr/local/bin/../datadir
dirname(rel2abs($0)):/usr/local/bin/../datadir
$FindBin::RealBin:/var/tmp/mydir/../datadir

##</code><code>##

dirname(rel2abs($0)) . "/../datadir"

##</code><code>##

$FindBin::RealBin . "/../datadir"