A command (dd) to make a Centos (Linux) USB (U disk) boot disk

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