Bash script for setting exif photo date according to filename. Created for whatsapp images can be easily adjusted for every filename patterns.

whatsappExifDateFix.sh

#!/bin/bash
set -e          #Exit as soon as any line in the bash script fails

imageCounter=0
for filename in *.jpg
do
	imageCounter=$((imageCounter+=1))
	#extracting info from file name
	year="${filename:4:4}"
	month="${filename:8:2}"
	day="${filename:10:2}"
	#setting exif timestamp into file
	exiv2 -M"set Exif.Image.DateTime $year:$month:$day" $filename
	#set the file last modified timestamp 
	touch -t "$year$month$day""1500" $filename
done
echo "successfully set the correct timestamp in $imageCounter images"

Hi.
I was trying to sort this problem out and found this code which helped me a lot. It worked like charm without changing anything.
I have 100-s of photos with right date-time on their names, but wrong in exif data.
I tried to modify this code to set the "time" stamp as in the photo's name, but could not make it work.
I stuck on error: "touch: invalid date format ‘20220412 200618’"
The example file I am trying this on is "IMG_20220412_200618.jpg"
I declared 3 more variables: $hour, $min, $sec, then tweak around, but no luck.
Please, give me a clue how to implement this.
Thanks for your code =)