Files/Directories in Linux general permissions

Permissions

1. view ############# for file properties
   
   Ls-l Filename/ls-ld Dictionary
   -|rw-r--r--. | 1| Root|   Root| 46 | OCT 1 05:03 |filename
   — ————————— — ———— ———— —— ———————————— ————————
   1 2 3 4 5 6 7 8
   1. "-": File type
   -# #普通文件
   D # #目录
   C # #字符设备
   S # #套接字
   P # #管道
   B # #快设备
   L # #连接
   2. "rw-r--r--": File read and Write permissions ##########
   rw-|r--|r--
   *   $   @
   
   * Everyone's rights
   $ permissions for all groups
   @ Other People's permissions
   
   3. "1":
   File: The number of times the contents of the file have been recorded by the system, in the case of a soft link, here is 2 in other words, the number of times it needs to be deleted.
   To directory: The number of bytes of the file attribute in the directory
   4. "Root": File owner
   
   5. "Root": all groups of files
   
   6. "46": Size of File contents
   
   7. "Oct 1 05:03": The last time the file was modified
   8. "FileName": File name

2. File General Permissions # # #
U: File user can read and write to file
G: File group members are readable for files
O: Other people can read the file
U first match, G priority, O match when U,g mismatch

1.R/4 4 for R permissions
To file: You can view the characters in the file cat
To directory: You can view the directory of the information directory of files, etc.

2.w/2
To file: You can change the characters in the file
For directories: You can add delete files to the directory

3.x/1
To files: program actions that can run records within a file
To the directory: You can enter the directory
3. Modify the file permissions by character # # #
chmod ugo+/-rwx File | directory (-r) "Recursion"
chmod 777 File | directory (-r) "Recursion"

4. System default Permissions set # # # #
#从系统存在角度来说, the greater the open power, the higher the system's existence meaning
#从系统安全角度来说, the less open power, the higher the system security
#所以系统设定新建文件或目录会去掉一些权限
Umask #系统预留权限 Default 0022
Create a new directory permission: 777-umask
Create a new file permission: 777-umask-111 (kernel decision)
Setting mode
Umask # #查看系统保留权限默认为022
Umask 077 # #修改该系统保留权限为077, this setting is temporary and only valid in the current shell

Permanent setting Mode:
VIM/ETC/BASHRC # #shell
If [$UID-gt 199] && ["' id-gn '" = "' Id-un '"]; Then
Umask 002 # #普通用户umask
Else
Umask 022 # #超级用户umask
The fi

Vim/etc/profile # #系统
If [$UID-gt 199] && ["' id-gn '" = "' Id-un '"]; Then
Umask 002 # #普通用户umask
All else
Umask 022 # #超级用户umask
+ fi

Two files above Umask set values must be consistent
Source/etc/bashrc
Source/etc/profile #重新加载文件
Make the setting effective immediately

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Files/Directories in Linux general permissions