Linux redirection standard input and output, standard error

The standard input is the file descriptor 0. It is the input to the command, the default is the keyboard, or it can be the output of a file or other command.
The standard output is the file descriptor 1. It is the output of the command, the default is the screen, or it can be a file.
The standard error is file descriptor 2. This is the output of the command error, the default is the screen, also can be a file.

Common program errors and status outputs are standard errors.

REDIRECT Standard output:

LS >ls.out

REDIRECT Standard input:

The sort < name.txt//Sort command is given in the form of a redirect, but it can also be used to direct the corresponding

REDIRECT Standard error:

grep color File 2> result.out

Standard output and error output are integrated:

grep color File > Result.out 2>&1

Qtalk Background command:

Setsid/home/arsenal/software/qtalk/run.sh>~/qtalk.out 2>&1

Linux redirection standard input and output, standard error