linux–2– directory permissions from zero single row
1, sync memory data with the new to the hard drive
2. Execution Level Init
a:run Level 0: Shutdown
B:run Level 3: pure Command mode
C:run Level 5: Includes graphical interface mode
D:run Level 6: restart
init 3 Toggle Mode
3. File permissions:
Owner User, file owner
Group user groups
others other people
There are 3 kinds of permissions {
1.read Read
2.write Write
3.execute Execution
}
The account on the system and the general user, as well as the root user's information are recorded in the/etc/passwd file .
the personal password is recorded in the/etc/shadow file.
group names are recorded in the/etc/group file
4. Types of documents:
-: Normal file
D: Catalogue
B: Device file {
1.B character start block device, HDD, USB flash drive
2.C character start device, keyboard, mouse
}
L: Shortcut (soft connection)
5. Change user Group command: CHGRP = (Changes group)
6. Changing the file owner: chown = (change owner)
7. Change file permissions: chmod
8. Digital Permissions:
x=2 0-times = 1 executable
w=2 1-times = 2 writable
r=2 2-times = 4 readable
rwx = 4 + 2 + 1 = 7
-rwxrwxrwx
the first 3 rwx represent the owner of the directory owner
Middle 3 Group of owning groups representing directories
The next 3 digits represent others.
9. Directories and files {
permissions for files {
R: Can read the actual contents of the file, read the contents of the text
W: Can edit, add, modify the contents of the file
X: The file has permission to be executed
}
permissions for folders {
R: Can read the list of files directory, can not view the details, use the LS command
W: (This permission is very powerful for the folder directory)
can create a new file directory
You can delete files that already exist
can be renamed
can transfer files within a directory
X: You can enter the file directory, you can use the CD command
}
}
10, ordinary documents:
Plain text files, binary files, plain format files
11. Catalog Files
12. Link File
13. Equipment Files:
block devices: such as keyboards
character device files: such as keyboard
14. Socket (S)
15, Pipeline (P): The purpose is to resolve the program to access a file at the same time caused by errors
16. Common extension:
. sh script or batch file
tar,tar.gz,.zip,.tgz Packed compressed files
. html,.php Web File
linux–2– directory permissions from zero single row