code: public static boolean isLinux(String os) {
          if (os == null) {
              return false;
          }
          String operating = os.toLowerCase();
          return operating.contains("nix") || operating.contains("nux") || operating.contains("aix");
      }
docs: Checks whether the given operating system name is Linux, Unix, or AIX.
  
  @param os the operating system name (value of the {@code os.name} system property
  @return {@code true} if the os is Linux, Unix, or AIX, {@code false} otherwise.