I/O redirection in Linux

System settings

Default output device: Standard output,stdout,1

Default input device: standard input,stdin,0

Standard error Output:STDERR,2

Standard input: Keyboard

Standard output and Error output: Display

1. Output redirection  

>: Overwrite output

>>: Append output

If you can use set-c to prevent operational errors, the file presence cannot be overwritten function set +c can be closed

You can also use >| When you turn on set-c Force Overwrite

2. Error output Redirection

2> Coverage

2>> Append

3, that is, directional error and correct orientation

ls/varr >/tem/var3.out 2>/tem/err.out

OR

Redirect all outputs

&>

4. Input redirection

<

<<: Here documents usually << end or << EOF with end or EOF As the end prompt

Example: cat << END shows what will be written

Cat >>/tmp/myfile.txt << END Appends content redirection to be written to the /tmp/myfile.txt file

5. Command Pipeline

Enter the result of the previous command as the next command

Command 1 |   command 2 | Command 3 ...

Example:echo "Hello word" | tr ' A-Z ' A-Z '

echo ' Radhat ' | passwd--stdin user1 Change Password

6,tee from the standard input read data from the standard output output data and save to a file copy

Example:echo "Hello World" | tee/tep/hello.out

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I/O redirection in Linux