Per discussion on StackOverflow: http://stackoverflow.com/questions/3282498/how-can-i-detect-a-unix-like-os-in-java src/main/java/org/apache/commons/lang3/SystemUtils.java - changing the javadoc to say 'UNIX like' rather than POSIX as some of the listed UNIX like operating systems are not POSIX compatible
commons/proper/lang/trunk/src/main/java/org/apache/commons/lang3/SystemUtils.java