最近我自己搞了套nuc和nas，所需要重新装一个系统，为了炼丹还是选择了ubuntu，记录一下在mac下做启动盘的过程。
下载Ubuntu镜像文件：Ubuntu官网下载所需要的的镜像文件（iso），我用的ubuntu-22.04-desktop-amd64.iso
然后开始处理U盘：
找到自己的盘：
diskutil list /dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.3 GB disk0 1: EFI EFI 314.6 MB disk0s1 2: Apple_APFS Container disk1 500.0 GB disk0s2 /dev/disk1 (synthesized): #: TYPE NAME SIZE IDENTIFIER 0: APFS Container Scheme - +500.0 GB disk1 Physical Store disk0s2 1: APFS Volume Macintosh HD 15.2 GB disk1s1 2: APFS Snapshot com.apple.os.update-... 15.2 GB disk1s1s1 3: APFS Volume Macintosh HD - Data 400.9 GB disk1s2 4: APFS Volume Preboot 620.1 MB disk1s3 5: APFS Volume Recovery 1.1 GB disk1s4 6: APFS Volume VM 17.2 GB disk1s5 /dev/disk2 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *124.0 GB disk2 1: Microsoft Basic Data 3.7 GB disk2s1 2: EFI ESP 4.3 MB disk2s2 3: Microsoft Basic Data 307.2 KB disk2s3
比如我是/dev/disk2。
sudo diskutil umountDisk /dev/disk2 sudo diskutil eraseDisk ExFAT ud /dev/disk2
再制作启动盘：
hdiutil convert -format UDRW ubuntu-22.04-desktop-amd64.iso -o ubuntu-20.04-desktop-amd64
-format为生成文件的权限；UDRW :表示转换成有read/write的权限的镜像，-o 是输出的文件名，结束后会产生ubuntu-22.04-desktop-amd64.dmg文件，终端里面出现以下的成功信息：
hdiutil convert -format UDRW ubuntu-22.04-desktop-amd64.iso -o ubuntu-22.04-desktop-amd64 Reading Protective Master Boot Record (MBR : 0)… Reading GPT Header (Primary GPT Header : 1)… Reading GPT Partition Data (Primary GPT Table : 2)… Reading ISO9660 (DOS_FAT : 3)… ............................................................................................................................................................................................................................................................. Reading Appended2 (C12A7328-F81F-11D2-BA4B-00A0C93EC93B : 4)… ............................................................................................................................................................................................................................................................. Reading Gap1 (DOS_FAT : 5)… ............................................................................................................................................................................................................................................................. Reading Ubuntu 22.04 LTS amd64 (Apple_ISO : 6)… ............................................................................................................................................................................................................................................................. Reading GPT Partition Data (Backup GPT Table : 7)… ............................................................................................................................................................................................................................................................. Reading GPT Header (Backup GPT Header : 8)… ............................................................................................................................................................................................................................................................. Elapsed Time: 5.440s Speed: 640.7MB/s Savings: 0.0%
写入U盘：
$ sudo dd if=ubuntu-20.04-desktop-amd64.img of=/dev/rdisk2 bs=1m
注意of=后边的地址是U盘的挂载地址，在diskutil list命令中可看到；另外disk2 -> rdisk2。
sudo dd if=ubuntu-22.04-desktop-amd64.dmg of=/dev/rdisk2 bs=1m 3485+1 records in 3485+1 records out 3654957056 bytes transferred in 90.399920 secs (40430977 bytes/sec)
到这里基本整个启动盘就做完了。