Linux (6), Funnel Family & pipelines

Funnel Family output redirection

Enter the correct command result into the file.

Notice:echo -- display a line of text

>>

Append redirect, append to last row.

[[email protected] fangqihan]# cat 1.txt haha[[email protected] fangqihan]# echo 'hello linux' >> 1.txt [[email protected] fangqihan]# cat 1.txt hahahello linux

2>>

Only the wrong command results are entered into the file

[[email protected] fangqihan]# asas 'wewe' >> 1.txt -bash: asas: 未找到命令[[email protected] fangqihan]# cat 1.txt hahahello linux[[email protected] fangqihan]# asas 'wewe' 2>> 1.txt [[email protected] fangqihan]# cat 1.txt hahahello linux-bash: asas: 未找到命令

&>>

The results of the command return are entered into the file, whether the command is correct or not.

[[email protected] fangqihan]# echo  'wewe' &>> 1.txt [[email protected] fangqihan]# cat 1.txt hahahello linux-bash: asas: 未找到命令wewe

Method 2:

commands >>3.txt 2>>3.txt

>

Standard redirection, empty first, then write content.

[[email protected] fangqihan]# cat 1.txt abcd[[email protected] fangqihan]# echo 'hello linux' > 1.txt [[email protected] fangqihan]# cat 1.txt hello linuxset -C　 　  # 开启防止标准重定向功能，无法覆盖已存在的文件    [[email protected] fangqihan]# echo 'haha' > 1.txt     -bash: 1.txt: 无法覆盖已存在的文件set +C          # 关闭此功能

Input redirect

Notice:tr -- translate or delete characters

<

Get input from a file

[[email protected] fangqihan]# cat 1.txt hahahello linux-bash: asas: 未找到命令wewe[[email protected] fangqihan]# tr 'a-z' 'A-Z' < 1.txt HAHAHELLO LINUX-BASH: ASAS: 未找到命令WEWE

<<

<<: Here is the document that is generated here, with cat >> 1.txt << EOF multiple rows appended.

Pipeline |

The output of the command before the pipeline is treated as an input to the latter command.

# example 1：对给定的字符串进行小写转换成大写字母[[email protected] ~]# echo hello linux |tr a-z A-Z HELLO LINUX# example 2：取出文件内容并将小写字母转换成大写展示出来[[email protected] ~]# cat 1.txt huckENDabc[[email protected] ~]# cat 1.txt | tr a-z A-ZHUCKENDABC# example 3：取出文件中的第3-4行的内容[[email protected] ~]# cat -n 1.txt      1  huck     2  END     3  a     4  b     5  c[[email protected] ~]# head -4 1.txt |tail -2ab

|tee: read from standard input and write to standard output and files

[[email protected] ~]# echo hi,my name is ham |tee 2.txthi,my name is ham

Linux (6), Funnel Family & pipelines