"Linxu learning 007" Pipeline and redirection

First, the pipeline

The use of pipelines makes it easy to implement the output of one program as input to another program. Pipe symbol for ' | ', usage:

Commend | Commend | commend| ......

Example:

[Email protected]:~$ echo "ABCDEFG" | TR [: Lower:] [: Upper:]abcdefg[email protected]:~$ more/etc/passwd | grep ' Kdyzm ' kdyzm:x:1000:1000:kdyzm,,,:/home/kdyzm:/bin/bash[email protected]:~$

Second, redirect

Online Documentation: HTTP://PUBS.OPENGROUP.ORG/ONLINEPUBS/9699919799/UTILITIES/V3_CHAP02.HTML#TAG_18_07

1. Input and output description

English name    Chinese name    file descriptor stdin     standard input         0STDOUT    standard output         1STDERR    standard error Output      2

2. Input redirection

<     : input redirection (redirecting input) <<    : Document here (here-document)

(1). Enter redirection

[Email protected]:~$ tr [: Lower:] [: Upper:] </etc/passwd

(2). Documentation here

[Email protected]:~$ tr [: Lower:] [: Upper:] << eof> nihao> hello> world> eofnihaohelloworld[email prote cted]:~$

3. Output redirection

>        : Overwrite output redirection >>       : Append output redirect &>: Redirect       error output and standard output to the same file 2>       : Error output redirect (overwrite) 2>>      : Error output redirect (append) |>       : Overwrite output redirection is still allowed with SET-C set

Description

Overwrite output redirection is allowed by default, but there is a clear security issue, so you can use the switch to control

Set-c    : When using output redirection, overwrite output redirection (>) set +C is not allowed if the file already exists    : Turn off the function above

If you also want to use overwrite output redirection if SET-C is set, then use |>.

4. How do I save the output to a file while it is displayed on the screen?

Tee

Example:

Tee/tmp/temp.txt

This article is from the "stolen A Plum blog" blog, please be sure to keep this source http://kdyzm.blog.51cto.com/8316029/1740150

"Linxu learning 007" Pipeline and redirection