linux–2– directory permissions from zero single row

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