list-boot-options

#!/bin/bash
# Executing grep every time is a little slow, but bash regex doesn't support
# lazy evaluation and it's not worth rewriting...

IFS=''  # Preserve whitespace for read

while read p; do  # Read /boot/grub/grub.cfg line by line
    LINE_REGEX=`echo $p | grep -Po "menuentry ['\"]\K.+?(?=['\"])"`
    if [ "$LINE_REGEX" ]; then 
        # Submenu lines begin with a tab, so lazy method is to check for that
        if [ ${p::1} = '	' ]; then
            echo "  $LINE_REGEX"
        else
            echo $LINE_REGEX
        fi
    fi
done < /boot/grub/grub.cfg