梁剑的Blog

升级到Snow Leopard的时候，找到的是dmg文件。
Mac自带的磁盘工具支持将dmg写入到USB stick，并用USB stick来引导安装。

当时就想，是不是iso文件也可以这样做？
今天准备装Ubuntu 10.10的时候，在Ubuntu的安装向导中找到了答案：

1. Download the desired file
2. Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)
3. Convert the .iso file to .img using the convert option of hdiutil (e.g.,hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso)
4. Note: OS X tends to put the .dmg ending on the output file automatically.
5. Run diskutil list to get the current list of devices
6. Insert your flash media
7. Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)
8. Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)
9. Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg).
10. Using /dev/rdisk instead of /dev/disk may be faster.
    If you see the error dd: Invalid number '1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M.
    If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the ‘Disk Utility.app’ and unmount (don’t eject) the drive.
11. Run diskutil eject/dev/diskN and remove your flash media when the command completes
12. Restart your Mac and press alt while the Mac is restarting to choose the USB-Stick

从第5步起，也可以直接用“磁盘工具”代替
原文地址：http://www.ubuntu.com/desktop/get-ubuntu/download

另外，上文也提到了在Windows下将iso做成可引导USB stick的方法。用这个小工具应该比UltraISO要方便吧。