Linux management and I/O redirection

/ o:

System settings

Default input device: standard input, stdin,0

Default output device: Standard output, stdout,1

Standard error Output: stderr,2

belong to different data streams

Standard input: Keyboard

Standard output and Error output: Display

I/O redirection:

Output redirection:

>: Overwrite Output

>>: Append Output

2>: Error Output

2>>: Append error output

Normal output

Ls/usr >/tmp/var.out

Set

-C: Prohibit overwrite redirection for already existing files;

+c: Allow overwrite output

Force overwrite output

LS/USR >| /tmp/var.out

Error output

Ls/varr 2>/tmp/var2.out

Directional standard output and standard error output

Ls/varr >/tmp/var3.out 2>/tmp/err.out

&>: Redirect standard output or error output to the same file

Ls/varr &>/tmp/var4.out

Input redirect

<: normal input

<<:here Document

Normal input

Tr ' A-Z ' A-Z ' </etc/fstab

Output content to File

Cat >>/tmp/myfile.txt << EOF

Linux management and I/O redirection