The whole process can be divided into three steps:
The first step is to prepare an 8G USB flash drive, a machine with Linux system and a CD image file of Linux system.
The second step is to determine the hardware location of the USB flash drive (device location)
First insert the USB flash drive into the Linux machine, and then use the command
fdisk -l
[root@trust ~]# fdisk -l
Disk /dev/sda: 200 GiB, 214748364800 bytes, 419430400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xcd16d148
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 2099199 2097152 1G 83 Linux
/dev/sda2 2099200 419430399 417331200 199G 8e Linux LVM
Disk /dev/mapper/cl-root: 70 GiB, 75161927680 bytes, 146800640 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/cl-swap: 2 GiB, 2181038080 bytes, 4259840 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sdb: 28.8 GiB, 30943995904 bytes, 60437492 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x4a716bd3
Device Boot Start End Sectors Size Id Type
/dev/sdb1 * 63 60435647 60435585 28.8G b W95 FAT32
Disk /dev/mapper/cl-home: 127 GiB, 136327462912 bytes, 266264576 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
[root@trust ~]# dd if=/opt/CentOS-8.4.2105-x86_64-dvd1.iso of=/dev/sdb