Luxio provides extremely low-level bindings to many POSIX system calls,
returning results as uncooked as possible, and even returning errno so you
can handle things yourself.  This is often not very nice to use.  To safe
your santity, there is the luxio.simple wrapper, which makes things
delightful and lovely.

> sio = require "luxio.simple"
> h = sio.open("/etc/motd", "r")

Nice tostring methods:

> =h
file descriptor: 3 (/etc/motd)

Familiar interface for reading, writing, closing:

> =h:read "*l"
The programs included with the Debian GNU/Linux system are free software;
> h:close()

Open a file for read/write, c = O_CREAT, e = O_EXCL.  The third parameter
is what mode to give it when creating.  In luxio.simple, permission modes can
be passed as strings you might pass to chmod, or octal strings, or just
numbers.  If you're really sick, you can pass the string ls -l produces.

> h = sio.open("testfile", "rwce", "u+rw")
> =h
file descriptor: 3 (testfile)

Various stat() functionality exists.  Even fstat() is provided:

> for i, v in pairs(h:stat()) do print(i,v) end
dev	65027
rdev	0
nlink	1
atime	1372260763
ctime	1372260763
blksize	4096
ino	7079478
mtime	1372260763
gid	1000
blocks	0
mode	33152
uid	1000
size	0

> h:close()
> sio.unlink "testfile"

Standard IO streams are provided, too.

> =sio.stdout
file descriptor: 1 (<stdout>)
> sio.stdout:write "Hello, world!\n"
Hello, world!

Pipes and socketpairs are supported.  Even datagram socketpairs are.

> r, w = sio.pipe()
> =r
file descriptor: 3 (<anonpipe 0/reader>)
> =w
file descriptor: 4 (<anonpipe 0/writer>)
> w:write "hello!\n"
> =r:read "*l"
hello!
> r:close(); w:close()
> sock1, sock2 = sio.socketpair(luxio.SOCK_DGRAM)
> =sock1
file descriptor: 3 (<datagram socketpair 0/0>)
> =sock2
file descriptor: 4 (<datagram socketpair 0/1>)
> sock1:close(); sock2:close()

Use the getaddrinfo() interface to connect to services while ignoring the
trickyness of different protocols:

> sock = sio.connect("www.lua.org", "http")
> =sock
file descriptor: 5 (<socket ipv6/tcp 2a02:40:41::5 80 connected>)
> sock:write "HEAD / HTTP/1.1\r\nHost: www.lua.org\r\nConnection: Close\r\n\r\n"
> return sock:read "*a"
HTTP/1.1 200 OK
Server: Zeus/4.3
Content-Type: text/html
Content-Length: 2701
Accept-Ranges: bytes
Last-Modified: Wed, 15 May 2013 13:19:29 GMT
Date: Wed, 26 Jun 2013 15:44:12 GMT
X-Varnish: 1466339377
Age: 0
Via: 1.1 varnish
Connection: close

Luxio also features server sockets, UNIX domain sockets, directory
enumeration, fork/exec, a nifty subprocess module (allows you to spawn
processes and control all of their file descriptors, including stdin/out etc),
a managed interface to poll(), and bags of other goodles.