Ubuntu – How to “reboot into” the non-default operating system in a dual-boot configuration

• You have to edit your grub first.

  sudo gedit /etc/default/grub
  

• Search for the line GRUB_DEFAULT=0 and modify it to GRUB_DEFAULT=saved

• Update your grub using the following command.

  sudo update-grub  
  

• Now create a script file,

  sudo gedit switch-to-windows.sh
  

• Then add these lines.

  #!/bin/bash
  WINDOWS_ENTRY=`grep menuentry /boot/grub/grub.cfg  | grep --line-number Windows`
  MENU_NUMBER=$(( `echo $WINDOWS_ENTRY | sed -e "s/:.*//"` - 1 ))
  sudo grub-reboot $MENU_NUMBER
  sudo reboot
  

• Make the script executable.

  sudo chmod +x switch-to-windows.sh
  

• And now you can run this script from terminal to reboot into windows.

  ./switch-to-windows.sh
  

• Or you can execute the following command in your terminal

  sudo grub-reboot X  
  

• Where X is the menuentry position of the OS you want to restart in from the GRUB menu.(starting with 0 as the first entry)

For Example:

• If this is your grub menu and if you want to boot into windows you should give the value of X as 5.

• sudo grub-reboot 5

  

• You can also create a launcher for the above command,so that double clicking the launcher will reboot into windows.

Because you've installed Ubuntu using Wubi, you need to modify the settings of Windows boot loader, not GRUB.

Grab a Windows repair DVD. Boot from it, and select the option to open a DOS command-line. Type this:

bcdedit /timeout 10

This will change the time out of the Windows' bootloader to ten seconds, giving you enough time to select Windows.

Once you've booted Windows, you can change the default back to Windows, in the same way that you had originally changed the default to Ubuntu:

1. Right click on Computer and select Properties
2. Click Advanced System Settings
3. Click on the Settings button under Startup and Recovery
4. Select Windows.

Reference:

• This Ubuntu Forums thread