Help With BASH Script Boot Menu Please?

[GTR2Fan]

Hi,

I've recently started running my favourite three Pi OSes from an external USB hard drive but, at the moment, the only way I can choose which OS to boot is by SSH-ing in to the Pi from my Windows PC using Putty.

The three OSes are mounted as '/dev/sda2', '/dev/sda3', and '/dev/sda4', so to simplify matters, I've created directories on the boot SD card named 'sda2', 'sda3', and 'sda4' containing copies of the original boot files for the relevant OS with appropriate 'root=' modifications.

At present, to change OS, I SSH in with Putty and type...

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cd /boot
sudo rm *.*
cd sda2
sudo cp *.* /boot
sudo reboot

...to launch Raspbmc,

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cd /boot
sudo rm *.*
cd sda3
sudo cp *.* /boot
sudo reboot

...to launch Raspbian, and

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cd /boot
sudo rm *.*
cd sda4
sudo cp *.* /boot
sudo reboot

...to launch RetroPie.

Unfortunately, I have zero knowledge of BASH scripting, but I was wondering if it's possible to write a simple text-based menu system in BASH that goes on the SD card to allow this to be achieved directly from the Pi, both on initial boot-up, and on exit from each OS.

For example...

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Raspberry Pi Boot Menu
======================
    PRESS A KEY... 
     1/ Raspbmc
     2/ Raspbian
     3/ RetroPie
======================

...with a 10 second pause before launching the previously loaded OS if no key is pressed.

If someone is prepared to help me with the scripting then I'd be happy to throw together a guide for the Raspberry Pi forum to help others achieve the same thing.

[DougieLawson]

Take a look at /usr/bin/raspi-config that's a bash script that has all sorts of text based menus.

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  if [ $ASK_TO_REBOOT -eq 1 ]; then
    whiptail --yesno "Would you like to reboot now?" 20 60 2
    if [ $? -eq 0 ]; then # yes
      sync
      reboot
    fi
  fi

[GTR2Fan]

Thank you. I hadn't realised that was generated by a BASH script. I'll take a look and have a fiddle.

[GTR2Fan]

Well, I've made a little headway.

After attempting to simultaneously learn BASH and write it, I've temporarily given up on the idea of writing an all-in-one script to deal with the above, and prepended '#!/bin/bash' to all of the above code snippets and saved them out as files named 'os1', 'os2', and 'os3' respectively into all three OS boot file directories.

At least I can now just type, for example, '/boot/os1' at a terminal prompt to reboot in to Raspbmc.

I guess that's about as far as my current level of numptiness is going to get me.