DB<100> $path='var1/var2/var3'             # input
 => "var1/var2/var3"

  DB<102> @path=split /\//,$path             # extract path
 => ("var1", "var2", "var3")

  DB<103> $hash_ref->{var1}{var2}{var3}=42   # init nested test-hash 
 => 42

  DB<104> $node=$hash_ref                    # set start
 => { var1 => { var2 => { var3 => 42 } } }

  DB<105> $node=$node->{$_} for @path        # walk down path
 => ""

  DB<106> $node                              # check result
 => 42