Soft connections and hard connections

Hard Connect:

1, can only create files, can not be applied to the directory;

2, can not cross the file system;

3, creating a hard connection will increase the number of times the file is connected;

Symbolic Connection:

1, can be applied to the directory;

2, can cross file system;

3, will not be increased the number of files are connected;

4, its size is the number of characters that the pointing path contains;

To create a connection command:

ln [-s-v] SRC DEST

Du shows a file system or each directory occupies the overall disk space size, the size of each directory

Du-s shows that sub-files in a directory occupy the size of disk space, the entire directory size

DF Report File system disk uses space size, default display file Block size

-I: Display inode number

-H: Displays the file system size

-P: Display content on the same line

Device files:

Block Device B: Devices that are randomly accessed by block, such as disks

Character Device C: Devices that are accessed by character, such as a keyboard

Device files are distinguished by the main device number and the secondary device number

Main device number (major numbers): Indicates the same type of device

Minor number: represents different devices in the same type of device

command to create a block device

Mknod: Creating a special file for a block or character device

Mknod [OPTION..] NAME TYPE [MAJOR | MINOR]

-M MODE: Device permissions granted when a block device is created

-P: Creating a piping device FIFO

#echo "Hello" >>/dev/pts/1

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Soft connections and hard connections