[Linux] Shell requests a web page

File descriptor

• 0: standard input
• 1: standard output
• 2: error output

For example

1 exec 8<> /dev/tcp/www.baidu.com/80
2 echo -e "GET / HTTP/1.0\n" 1>& 8
3 cat 0<& 8
4 exec 8<& -

• Create a new file descriptor 8
• <>: Sending a request, and receiving response data
• 1 kernel will perform after establishing a connection with Baidu socket
• -e: Recognition \ n linefeed
• GET: request method
• /: Request Home
• Sends a request to the kernel data after performing two Baidu, Baidu response descriptor is present in the 8
• 3 performing a read response information
• 4 Close the file execution

reference

linux redirection, exec achieve access Baidu home page

https://blog.csdn.net/weixin_43294560/article/details/102943327

A linux standard input output standard issue

https://lists.ubuntu.com/archives/ubuntu-zh/2012-June/012147.html

On Eight shell I / O redirection

https://blog.csdn.net/taiyang1987912/article/details/39401265