reboot-to-os

#!/usr/bin/env bash

declare -a entries
mapfile -t entries < <(awk 'BEGIN {
  l=0
  menuindex= 0
  stack[t=0] = 0
}

function push(x) {
  stack[t++] = x
}

function pop() {
  if ( t > 0 ) {
    return stack[--t]
  } else {
    return ""
  }
}

{

if ( $0 ~ /.*menu.*{.*/ ) {
  push( $0 )
  l++
} else if ( $0 ~ /.*{.*/ ) {
  push( $0 )
} else if ( $0 ~ /.*}.*/ ) {
  X = pop()
  if( X ~ /.*menu.*{.*/ ) {
     l--
     match( X, /^[^'\'']*'\''([^'\'']*)'\''.*$/, arr )

     if ( l == 0 ) {
       print menuindex ": " arr[1]
       menuindex++
       submenu=0
     } else {
       print "  " (menuindex-1) ">" submenu ": " arr[1]
       submenu++
     }
  }
}

}' /boot/grub/grub.cfg)

declare selected_entry
selected_entry="$(printf "%s\n" "${entries[@]}" | fzf --cycle --tiebreak=begin,chunk,length --layout=reverse | xargs)"

sudo grub-reboot "$(echo "${selected_entry}" | cut -d':' -f1)"

read -p "Reboot Now? [yN] " -n 1 -r
echo
case $REPLY in
    y|Y)
      echo
      echo "[countdown] rebooting in..."

      secs=$((5))
      while [ $secs -ge 0 ]; do
        sleep 1 &
        printf "\r  %d " $(( secs ))
        secs=$(( secs - 1 ))
        wait
      done
      echo
      sudo reboot
      ;;

    *)
      echo "Next reboot would boot to:"
      echo "  ${selected_entry}"
      ;;
esac