Finding a data path:

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