| P This forces the value of the parameter name to be interpreted as | a further parameter name, whose value will be used where appro- | priate. If used with a nested parameter or command substitution, | the result of that will be taken as a parameter name in the same | way. For example, if you have `foo=bar' and `bar=baz', the | strings ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be | expanded to `baz'.
