1. Basic instructions
Add group
Basic grammar
groupadd group name
Function description
Add group
Practical demonstration
Add members to the group
Modify file owner
Basic grammar
chown user name file name
chown user name: group name file name
Function description
Change file owner
Change user owner and all groups
Actual demonstration
Modify the file group
Basic grammar
chgrp group name file name
Function description
The actual demonstration of the group where the file is modified
Modify permissions
Basic grammar
chmod u=rwx,g=rx,o=x file directory name
chmod o+w file directory name
chmod ax file directory name
chmod permission digital file directory name
Function description
Modify the group where the file is located.
Note:
Method 1: u: Owner g: All groups o: Others a: Everyone (the sum of u, g, and o)
* Method 2: Rule: r=4 w=2 x =1,rwx=4+2+1=7 The authority is expressed by a number, through + add authority through-delete authority *
For example: chmod 751 file directory name = chmod u=rwx,g=rx,o=x file directory name
Actual demonstration
2. Detailed explanation of file display content
probably
-rw-r--r--. 1 stu01 student 2554 12月 3 05:42 a.txt
Permission display content:
-rw-r--r--
1) The 0th bit determines the file type (d (directory),-(normal file), l (hard link), c (character device example: mouse and keyboard), b (block file, hard disk))
2) No. 1-3 Bit confirms that the owner (the owner of the file) has permissions for the file.
3) The 4th to 6th digits determine that the group (of the same user group) has the permission of the file
4) The 7th-9th digits determine that other users have the permission of the file
File display:
1 stu01 student 2554 12月 3 05:42 a.txt
1) If the first part is a file, it means the number of hard links. If it is a directory, it means the number of subdirectories.
2) The second part means all users.
3) The third part means all group names.
4) The fourth part means 4096 if the directory is 4096. , If the file means the file size
5) The fifth part 12月 3 05:42means the last modification time
6) The sixth part means the file name
Three, detailed explanation of rwx permissions
1. rwx acts on the file
1) [r] stands for readable (read): can be read, view
2) [w] stands for writable (write): it can be modified, but it does not mean that the file can be deleted. The prerequisite for deleting a file is the file The directory where you have write permission can delete the file.
3)[x] stands for execute: can be executed
2, rwx acts on the directory
1)[r] stands for readable (read): can be read, ls view the contents of the directory
2) [w] stands for writable (write): can be modified, create + delete + rename the directory in the directory
3) [x] stands Executable (execute): you can enter the directory