MySQL database -------- simply understand the relevant information of the file

Author's Foreword

 Welcome little cuties to come and learn from my gtiee Qin Boss (qin-laoda) - Gitee.com

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Table of contents

file information

file permissions

grant of authority

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Insert some little knowledge

1. cd .. can return to the previous directory or direct cd can also return to the previous directory

2. ..represents the directory of the previous layer .represents the directory of the current layer

file information

Some cuties in the last blog will find that there are many output contents when using the command ls -l, some cuties may not understand, I will introduce a little bit below

 Some cute people will find that color fonts can distinguish directories and files, and they will mess up. When creating folders and files, they will sometimes add a suffix and sometimes not. In principle, it is possible, but we will increase a lot when we are looking for files. Difficulty, so it is generally believed that files have suffixes, but folders do not. This is the potential rule

Below I will dissect it a little bit

file name

These are the file and directory names

file creation time or modification time

file size

When we use ls -hl, it will convert the qualified ones into units of k

owner and peers

It can be seen that there are two columns of different colors. The green one is the name of the creator (ourself), and the red one is the name of the same group (team).

number of paths

 These numbers represent how many paths the file you are looking for can be found

permissions

 These are the permissions, and I will focus on this below to explain

To understand this, you need to understand what these mean

 r ------- read

w ------------Modify

x ------------- execute

 grant of authority

1. Common law

u-------- represents the owner

g ---------Represents the same group

o ---------- on behalf of someone else

+ -----------Increase

- --------------reduce

= ------------modified to

Next we will introduce a command chmod

 In the above picture, I take the permission of modifying the a directory as an example

Use = to modify

 It can be seen that it is directly modified to, not increase and decrease

 

 The above method may be a little cute and I can’t remember it, so let me introduce the second method

digital method

 r  ------------4

w ---------------2

x -----------------1

-   ------------------0

 chmod 777 a The position of the first 7 represents u The position of the second 7 represents g The position of the third 7 represents o

7 =4+2+1 which is r+w+x

Summarize

The above is the relevant information of the file I introduced, if you don’t understand, you can chat with me in private

 

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Origin blog.csdn.net/m0_69984273/article/details/131509593