Macのbashでも出来るぞw

$ bash --version
GNU bash, version 3.2.17(1)-release (i386-apple-darwin9.0)
Copyright (C) 2005 Free Software Foundation, Inc.
$ exec 3<>/dev/tcp/www.google.com/80
$ echo -e "GET / HTTP/1.1¥n¥n">&3
$ cat <&3
HTTP/1.1 200 OK
Date: Fri, 14 May 2010 07:12:54 GMT
...