Don't feel bad. An entire module has sprung up based on this same misconception (and it was authored by some of the top Perl guys around). $0 is the name of the script, which Perl has to be able to open so Perl knows the correct path to it and doesn't hide it from you. argv[0] in the C code that implements Perl is "...perl" (not the script name) and may not have a full path and so $^X may not have a full path. See FindBin is broken (RE: How do I get the full path to the script executing?) for more.

        - tye (but my friends call me "Tye")