?  ~ diskutil list #确认烧刻的磁盘
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         1.0 TB     disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.0 TB     disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            10.9 GB    disk1s1
   2:                APFS Volume Preboot                 92.6 MB    disk1s2
   3:                APFS Volume Recovery                528.1 MB   disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4
   5:                APFS Volume Macintosh HD - 数据     378.5 GB   disk1s5

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *31.4 GB    disk2
   1:               Windows_NTFS 334                     31.4 GB    disk2s1

?  ~ sudo dd if=software/ISO/CentOS-7-x86_64-Minimal-1804.iso of=/dev/disk2 bs=1m
Password:
dd: /dev/disk2: Resource busy  ##如果提示resource busy，使用磁盘工具，点击“卸载”（非推出）即可。
?  ~ sudo dd if=software/ISO/CentOS-7-x86_64-Minimal-1804.iso of=/dev/disk2 bs=8192
115968+0 records in
115968+0 records out
950009856 bytes transferred in 250.868363 secs (3786886 bytes/sec)

macOS通过dd烧刻U盘启动盘