Shulou(Shulou.com)06/01 Report--

Today, I will talk to you about the operation methods of pipe characters, redirects and environmental variables, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following for you. I hope you can get something from this article.

Output redirection

History > / root/aaa.txt:history output information in the interface, input to aaa.txt,cat aaa.txt, you can see the content displayed by the history command, but overwrite

History > > / root/aaa.txt: append

Pipe symbol

Ps-ef | grep ssh

Give the information of the first command to the second command to use.

Wildcard character

Ls / dev/sda*: view all the things that start with sda

Ls / dev/sda?: check it followed by a certain character

Ls / dev/sda [0-9]: view a single number that matches to 0-9

Escape character

Backslash\: a variable after the backslash becomes a simple string:\ $

Single quotation mark'': escapes all variables as simple strings

Double quotation marks "": keep the attributes of the variables in them without escaping

Reverse quotation mark ``: returns the result after executing the command

Environment variable

Echo $PATH

The configuration file is in / etc/profile

After editing, you need to execute source / etc/profile to refresh

After reading the above, do you have any further understanding of pipe characters and redirects and how to manipulate environment variables? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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