制作ubuntu启动U盘：Windows,Mac osx ,Ubuntu

1.How to create a bootable USB stick on Windows

　　https://www.ubuntu.com/download/desktop/create-a-usb-stick-on-windows 

　　Before you begin, you need to download Ubuntu and, if you want, verify the download.

　　To run or install Ubuntu from a USB stick, the first thing you need to do is insert a USB stick with at least 2GB of free space into your PC.

　　The easiest way to put Ubuntu onto your stick is to use the Rufus USB installer. You’ll need to download and install and follow the instructions.

　　Download the Rufus USB installer

1. Open Rufus and select your USB stick in the 'Device' dropdown

   

2. Click the CD Rom icon next to the 'FreeDOS' dropdown, then find your downloaded Ubuntu ISO and click 'Open' and then 'Start'

   

3. Click 'Yes' when it asks to download Syslinux software

   

4. Click 'OK' to write in ISO Image mode

   

5. Confirm that your USB stick is selected and then 'OK' to continue

   

6. When it is finished, just restart your computer and start using Ubuntu, or you can install Ubuntu

   

2.How to create a bootable USB stick on macOS

　　https://www.ubuntu.com/download/desktop/create-a-usb-stick-on-macos

　　Before you begin, you need to download Ubuntu and, if you want, verify the download.

　　To run or install Ubuntu on a Mac from a USB stick, the first thing you need to do is insert a USB stick with at least 2GB of free space into your PC.

　　The easiest way to put Ubuntu onto your stick is to use the UNetbootin USB installer. You’ll need to download and install and follow the instructions.

　　Download the UNetbootin USB installer.

1. Download the 64-bit Ubuntu Desktop ISO

2. Launch UNetbootin and allow the osascript to make changes

   

3. Select the ‘Diskimage’ radio button and then click the '...’ button

   

4. Select the Ubuntu ISO file you downloaded and click 'Open'

   

5. Then select your flash drive in the bottom row and click 'OK'

   Tip: If you are unsure which one is your flash drive, in a terminal you can type

   $diskutil list

   with the drive not inserted and then inserted to see which one it is.

   

6. After UNetbootin finishes, click ‘Exit’ and restart your Mac

   

7. Press alt/option key while the Mac is restarting to choose the USB stick to try or install Ubuntu

　How to install Ubuntu on MacBook using USB Stick

3.How to create a bootable USB stick on Ubuntu

　　https://www.ubuntu.com/download/desktop/create-a-usb-stick-on-ubuntu

　　To create a USB stick from which you can install Ubuntu, you must first download Ubuntu and, if you want, verify the download.

　　Then, follow these instructions:

1. Insert a USB stick with at least 2GB of free space

2. Open the dash and search for Startup Disk Creator

3. Select the Startup Disk Creator to launch the app 中文叫“启动盘创建器”

        

4. Click 'Other' to choose the downloaded ISO file if it isn’t found automatically, select the file and click 'Open'

   

5. Select the USB stick in the bottom box and click 'Make Startup Disk' and then 'Yes'

   

6. That's it! When the process completes, you'll be ready to restart your computer and begin installing Ubuntu