How to change SD card content without access to working machine

Hi Guys,
I put this script in profile.d and my machine can't launch to the desktop.
 

#!/bin/bash

while true
do
str=`ls /home/lufa/Shared/QT/myapp* | sort -n -t _ -k 2 | tail -n1`
if [ ! `pgrep $str` ] ; then
$str
fi
sleep 30
done

It seems that this file prevent to run desktop. I can't connect to my board by UART terminal and WiFi

What is your suggestion? I am thinking to explore SD card, then change in this script true->false and then it should work. However, what tools can I use to explore the SD card which contains OS image? And is it a fully safe way?

Or maybe I should mount this SD card on some other linux device and I will able to edit it??

I managed to fix it -  just mount this SD card on some linux machine and edit...so it is easy but I am not pro user