The somewhat longer answer is that the OS (or filesystem implementation) is the ultimate authority on what the filesystem implementation really does. With a physical system check you can use the Cwd module and a cwd() combined with a pwd() to let the operating system figure out the correct interpretation.

An easier method using the Cwd method, albeit with the same limitation of being a filesystem-based implementation, is through the use of the abs_path method. For example:

# perl -MCwd=abs_path -le 'print abs_path("/usr/local/src/../bin/fnurg
+le")'
/usr/local/bin/fnurgle
[download]

perl -le 'print+unpack("N",pack("B32","00000000000000000000001000100010"))'