The standard inputs and outputs of Linux are as follows
When we execute commands in Linux, the commands are output to the console by default, and many times we need to output the commands to other devices, such as the most common in the file, or in the file. That's when you need to redirect the input and output of Linux.
Frequently used file redirection commands:
Command >file: Standard output redirected to a file, error still output screen
Command >>file: Standard output redirected to a file (append)
Command 1>file1: Standard output redirected to a file
Command 2>>file2: Standard error redirected to a file (append)
Command 1>file 2>&1: standard output and standard error Redirect to a file together
Command>>file 2>&1: Standard output and standard error redirected to a file (append)
Command < File1 >file2: File1 as standard input, file2 as standard output
Command <file: File as standard input
Note: The above command>file 2>&1 can be modified to Command>file 2>>file
Reference
Http://www.cnblogs.com/chengmo/archive/2010/10/20/1855805.html
Inputs from Linux are redirected from orientation and output