linux基础符号
#
* root用户命令提示符
```
[root@wenhaha wenhaha]#
```
$
* 普通用户命令提示符
```
[wenhaha1@wenhaha wenhaha]$
```
* awk中表示列
```
[wenhaha1@wenhaha wenhaha]$ cat wenhaha1.txt
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
-bash: ech: command not found
[wenhaha1@wenhaha wenhaha]$ awk ‘{print $1}‘ wenhaha1.txt
123343
wenhaha
-bash:
```
>
* 标准输出重定向
```
[root@wenhaha wenhaha]# echo wenhaha > wenhaha1.txt
[root@wenhaha wenhaha]# cat wenhaha1.txt
wenhaha
```
* 错误输出重定向
```
[root@wenhaha wenhaha]# ech > wenhaha1.txt
-bash: ech: command not found
[root@wenhaha wenhaha]# cat wenhaha1.txt
[root@wenhaha wenhaha]# ech 2> wenhaha1.txt
[root@wenhaha wenhaha]# cat wenhaha1.txt
-bash: ech: command not found
```
*追加输出重定向
```
[root@wenhaha wenhaha]# cat wenhaha1.txt
123343 3423543 45345 345
[root@wenhaha wenhaha]# echo "wenhaha wenhaha wehan wehshdf " >> wenhaha1.txt
[root@wenhaha wenhaha]# cat wenhaha1.txt
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
```
* 2>>错误追加输出重定向
```
[root@wenhaha wenhaha]# cat wenhaha1.txt
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
[root@wenhaha wenhaha]# ech "wenhaha wenhaha wehan wehshdf " >> wenhaha1.txt
-bash: ech: command not found
[root@wenhaha wenhaha]# ech "wenhaha wenhaha wehan wehshdf " 2>> wenhaha1.txt
[root@wenhaha wenhaha]# cat wenhaha1.txt
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
-bash: ech: command not found
```
<
* 输入重定向
```
[root@wenhaha wenhaha]# echo "123343 3423543 45345 345" > wenhaha1.txt
[root@wenhaha wenhaha]# column -t < wenhaha1.txt
123343 3423543 45345 345
```
* 追加输入重定向
```
[root@wenhaha wenhaha]# echo << wenhaha
> wefkwejfksd
> wehfsdfs
> wenhaha
```
|
* 管道
```
[root@wenhaha wenhaha]# cat wenhaha1.txt | wc -l
3
[root@wenhaha wenhaha]# wc -l < wenhaha1.txt
3
```
* | xargs
```
[root@wenhaha wenhaha]# ls wenhaha1.txt |xargs wc -l
3 wenhaha1.txt
[root@wenhaha wenhaha]# wc -l wenhaha1.txt
3 wenhaha1.txt
```
&&
```
[root@wenhaha wenhaha]# ech wenhaha && cat wenhaha1.txt
bash: ech: command not found
[root@wenhaha wenhaha]# echo wenhaha && cat wenhaha1.txt
wenhaha
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
-bash: ech: command not found
```
||
```
[root@wenhaha wenhaha]# echo wenhaha || cat wenhaha1.txt
wenhaha
[root@wenhaha wenhaha]# ech wenhaha || cat wenhaha1.txt
bash: ech: command not found
123343 3423543 45345 345
wenhaha wenhaha wehan wehshdf
-bash: ech: command not found
```
原文：https://www.cnblogs.com/wenhaha/p/12495391.html