linux file properties and permissions
In Linux system, there are three most common file permissions: read (R), write (W) and execute (X) permissions.
In Linux system, each file clearly defines the access rights of different identity users, which can be seen through ls command.
Example
➜ ls -l
As you can see, the first column of each line represents the permissions set by each file for different users, with 10 digits in total.
The first digit is used to represent the specific type of file, and the remaining 9 digits are used to set the read, write and execute permissions for different users.
File type
- – : general documents
- D: directory file
- L: linked files
- B: block device file, i.e. some interface devices that store data to provide random access to the system, such as hard disk, floppy disk, etc
- C: character device files, i.e. interface devices of some serial ports, such as mouse, keyboard, etc
- S: socket, data interface file, usually used for data transmission on the network
- P: FIFO file
Different user explanations
Three file access identities are: user, user group, and others
Digital representation of file permissions
The location of the three permissions will not be changed. You can use numbers to represent each permission.
- R = 4
- W = 2
- X = 1
The permissions of each identity are the sum of the three permissions.
Example
-rwxr-xr-x 1 ylspirit staff 39 Nov 2 20:14 test1.awk Owner permission is: 4 + 2 + 1 = 7
Group permission: 4 + 1 = 5
Other permission: 4 + 1 = 5
So the file permission is 755
More about Linux commands: Linux Commands Tutorial