Output the total number of currently running VirtualBox VMs, along with their names. This has been written with Vagrant in mind, where VMs are named `hostname_default_xxxxxxxxx` where only the value of `hostname` is relevant/recognisable.

vbox-status-check.sh

#!/bin/bash

machines=()

for machine in `VBoxManage list runningvms|cut -d" " -f 1`; do
  machines+=("$machine")
done

if [ ${#machines[@]} -eq 1 ]; then
  machinename=$(echo ${machines[@]} | cut -d'_' -f 1)
  echo "1 VM running: $machinename"
elif [ ${#machines[@]} -gt 1 ]; then
  echo "${#machines[@]} VMs running:"
  for machine in ${machines[@]}; do
    machinename=$(echo ${machine} | cut -d'_' -f 1)
    echo "$machinename\""
  done
else
    echo "No VMs running"
fi

To output the VBox status in terminal / ZSH (in the bottom right of the shell), add the following function to your theme-name.zsh-theme:

## Output VBox status
prompt_vm() {
  function vbox_status {
    echo `~/Vagrant/vbox-status-check.sh`
  }

  screen_w=$(tput cols)   # Get screen width
  screen_h=$(tput lines)  # Get screen height
  str=$(vbox_status)      # String to put in corner
  string_w=${#str}
  let "x = $screen_w - $string_w"

  tput sc               # Save current position
  tput cup $screen_h $x # Move to corner
  echo -ne $str         # Put string in the corner
  tput rc               # Go back to saved position
}

(see: http://stackoverflow.com/questions/24274456/zsh-sticky-prompt)

Then just call the function in build_prompt() like so:

build_prompt() {
  RETVAL=$?
  prompt_status
  etc...
  prompt_vm
  prompt_end
}

I find this particularly handy in avoiding the case where I have a VM or two left running in the background unused and draining my battery!

Example:

No VMs running: https://www.evernote.com/shard/s153/sh/6bc2d85e-d9b7-4a69-8cf5-b831b0bd90ec/680ec902d7d540f94ace5aff5d80f6f6/res/5b3085c0-f003-4d26-ac9c-2fbe4d4ecccf/skitch.png?resizeSmall&width=832

1 VM running: https://www.evernote.com/shard/s153/sh/cf208c18-9d87-47d0-afb2-4b19c28662b8/8758ef7286dfc035381ab1e2f5d3c28f/res/8a47b88d-cb78-4519-9857-040a7c93e91c/skitch.png?resizeSmall&width=832

Great job. I tried to get it to erase the prompt so that it wouldn't track up the terminal after you reach the bottom. On my mac it didn't support the erase commands though unfortunately.

Thanks for the tput related help @jcreasey!

I'll soon be looking at implementing this alongside Vagrant 1.6's 'global status' feature (rather than relying on VBox): http://www.vagrantup.com/blog/feature-preview-vagrant-1-6-global-status.html