How to Check if Script is run once device is booted?

I have a script I need to run once, and only once the phone is booted.

I have attempted init.qcom.post_boot.sh, init.sec.boot.sh, debuggerd, and finally mkshrc

While my script ran with debuggerd, I found that it ran every time debuggerd ran, which is not something I need to happen... thus when I stumbled upon /system/etc/mkshrc (the other 2 simply did not work)

What I found was, the script runs that one time, on boot... however, it also seems to run every time adb shell runs, along with (I assume) everytime shell is fired up... which is also undersireable.

So, what can I do in /system/etc/mkshrc to ensure my call to my script runs only the one time... at boot?

I thought about running a while loop to check for the getprop sys.boot_completed if it == 1 then dump a file somewhere, and through an if statement inside the looop to check for that file, if exists then exit, if not then run the next command... however, everywhere I am allowed to dump that file, it persists between boots, so that next command never runs again.

NOTE
Does not need root to do this, nor does my script need root to run (yes, I have confirmed)

CODE

BB=/system/xbin/busybox

MYPID=/mnt/sdcard/.kev-run



while [ `getprop init.svc.bootanim` == "stopped" ] ; do 


 # if the run file does not exist, and we are stopped


 if [ ! -e $MYPID ]; then


  # run the scripts, then create the run file


  LOG=/mnt/sdcard/Download/kevs-scripts.log


  $BB rm -f $LOG;


  $BB echo "Launching Kevs Scripts" >> $LOG;


  MY_SCRIPT


  # write the run file so we aren't running this everytime this file runs


  touch $MYPID;


  sleep 1;


 fi

done



# if we are still booting, delete the run file

while [ `getprop init.svc.bootanim` != "stopped" ] ; do


 # we're not done booting, remove our makeshift pid file and sleep a second


 $BB rm -f $MYPID;


 sleep 1;

done

Seems to be off to me