,unknown
osname,undetermined
aix,AIX
bsdos,BSD/OS
cygwin,Windows (Cygwin)
darwin,Mac OS X
dec_osf,Tru64
dragonfly,Dragonfly BSD
freebsd,FreeBSD
gnu,GNU Hurd
haiku,Haiku
hpux,HP-UX
irix,IRIX
linux,GNU/Linux
macos,Mac OS classic
midnightbsd,MidnightBSD
mirbsd,MirOS BSD
mswin32,Windows (Win32)
netbsd,NetBSD
openbsd,OpenBSD
os2,OS/2
os390,OS390/zOS
sco,SCO
vms,VMS
solaris,SunOS/Solaris
beos,BeOS
interix,Interix
gnukfreebsd,Debian GNU/kFreeBSD
nto,QNX Neutrino

