I/O REDIRECTION

There are always three default files open, stdin (the keyboard), stdout (the screen), and stderr (error messages output to the screen). Redirection simply means capturing output from a file, command, program, script, or even code block within a script and and sending it as input to another file, command, program, or script.

Numeric handles for file descriptors:

STDIN = 0 Keyboard input 
STDOUT = 1 Text output 
STDERR = 2 Error text output UNDEFINED = 3-9

REDIRECTION

command > filename                                               Redirect command output to a file

command >> filename                                             APPEND into a file 

command < filename                                               Pass a command from a text file

command A |  command B                                      Pipe the output from command A into command B 

command A & command B                                     Run command A and then run command B

command A && command B                                  Run command A, if it succeeds then run command B 

command A || command B                                      Run command A, if it fails then run command B

command 2 > filename                                            Redirect any error message into a file
command 2 >> filename                                          Append any error message into a file
command > file 2>&1                                               Redirect errors and output to one file
command > file 2<&1                                               Redirect output and errors to one file
command > fileA 2> fileB                                         Redirect output and errors to separate files
command 2>&1 >filename                   -------------->Wrong command                   

Redirect to NULL (hide errors)

command 2> /dev/null                                             Redirect error messages to NUL
command >/dev/null 2>&1                                      Redirect error and output to NUL
command >filename 2> /dev/null                           Redirect output to file but suppress error

We can also redirect to a printer with > PRN or >LPT1 

For more info read here and to read commands of linux shell and vbscript read here