Sorry, hope this is not excessively off-topic.  There's some BSD
content in here, I promise.

Re: uname in Perl, or $^O.  That var gives you the OS name.  The
question was raised about cross-platform programming.  If your system
supports the Perl POSIX module you have the uname function to emulate
uname.

There's also (look, a little BSD related content!) the Perl Power
Tools project, check out http://language.perl.com/ppt  .

The purpose of the project is to reimplement about 100 important BSD
utilities in a cross-platform manner for eventual packaging up with
perl so that Perl programmers may confidently do `uname`, or what have
you.  Unfortunately, the only uname implementation in the set
currently requires the POSIX module, but maybe eventually it will
support non-POSIX systems.  

Anyway, this project should make BSD Perl programmers happy because
someday soon you should be able to run more of your BSD system dependent
Perl programs on other systems without modification.