This code snippet changes the mode that your Ubuntu is started

changemode.py

#/usr/bin/env python3
#-*- encoding:utf-8 -*-

import sys, os

CHANGED = 0
NOT_CHANGED = 1
ERROR = 2
FILE_NAME = '/etc/default/grub'
LINES_TO_CHANGE = ['GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"', 'GRUB_CMDLINE_LINUX="', 'GRUB_TERMINAL=console']

def resultForMode(mode, index):
    if index == 0:
        if mode:
            return (LINES_TO_CHANGE[index]+'\n')
        else:
            return ("#"+LINES_TO_CHANGE[index]+'\n')
    elif index == 1:
        if mode:
            return (LINES_TO_CHANGE[index]+'"\n')
        else:
            return (LINES_TO_CHANGE[index]+'text"\n')
    elif index == 2:
        if mode:
            return ("#"+LINES_TO_CHANGE[index]+'\n')
        else:
            return (LINES_TO_CHANGE[index]+'\n')

def editLine(foundValue, mode):
    for i, value in enumerate(LINES_TO_CHANGE):
        if foundValue == value:
            return resultForMode(mode, i)

def main(args):
    argMode = args[1]
    mode = 2
    
    newText = ''
    
    if argMode == 'text':
        mode = 0
    elif argMode == 'display':
        mode = 1
		
    ret = NOT_CHANGED

    f = open(FILE_NAME, 'r')

    for line in f:
        canWrite = True
        for value in LINES_TO_CHANGE:
            if value in line: 
                newText += editLine(value, mode)
                canWrite = False
                
        if canWrite:
            newText += line
    
    f.close
    
    temp = open(FILE_NAME, 'w')
    temp.write(newText)
    temp.close
    
    os.system('update-grub')
    ret = CHANGED
    return (ret)

args = sys.argv
ret = main(args)
sys.exit(ret)